Enable clang-tidy as a sanity check, fix up all known failures

94 files changed, 1860 insertions, 1859 deletions

diff --git a/test/core/end2end/bad_server_response_test.cc b/test/core/end2end/bad_server_response_test.cc
index ea7857d8d7..04275e2c2a 100644
--- a/test/core/end2end/bad_server_response_test.cc
+++ b/test/core/end2end/bad_server_response_test.cc
@@ -135,8 +135,8 @@ static void on_connect(grpc_exec_ctx* exec_ctx, void* arg, grpc_endpoint* tcp,
                        grpc_tcp_server_acceptor* acceptor) {
   gpr_free(acceptor);
   test_tcp_server* server = (test_tcp_server*)arg;
-  GRPC_CLOSURE_INIT(&on_read, handle_read, NULL, grpc_schedule_on_exec_ctx);
-  GRPC_CLOSURE_INIT(&on_write, done_write, NULL, grpc_schedule_on_exec_ctx);
+  GRPC_CLOSURE_INIT(&on_read, handle_read, nullptr, grpc_schedule_on_exec_ctx);
+  GRPC_CLOSURE_INIT(&on_write, done_write, nullptr, grpc_schedule_on_exec_ctx);
   grpc_slice_buffer_init(&state.temp_incoming_buffer);
   grpc_slice_buffer_init(&state.outgoing_buffer);
   state.tcp = tcp;
@@ -161,15 +161,15 @@ static void start_rpc(int target_port, grpc_status_code expected_status,
   cq_verifier* cqv;
   grpc_slice details;
 
-  state.cq = grpc_completion_queue_create_for_next(NULL);
+  state.cq = grpc_completion_queue_create_for_next(nullptr);
   cqv = cq_verifier_create(state.cq);
   gpr_join_host_port(&state.target, "127.0.0.1", target_port);
-  state.channel = grpc_insecure_channel_create(state.target, NULL, NULL);
+  state.channel = grpc_insecure_channel_create(state.target, nullptr, nullptr);
   grpc_slice host = grpc_slice_from_static_string("localhost");
   state.call = grpc_channel_create_call(
-      state.channel, NULL, GRPC_PROPAGATE_DEFAULTS, state.cq,
+      state.channel, nullptr, GRPC_PROPAGATE_DEFAULTS, state.cq,
       grpc_slice_from_static_string("/Service/Method"), &host,
-      gpr_inf_future(GPR_CLOCK_REALTIME), NULL);
+      gpr_inf_future(GPR_CLOCK_REALTIME), nullptr);
 
   grpc_metadata_array_init(&initial_metadata_recv);
   grpc_metadata_array_init(&trailing_metadata_recv);
@@ -179,26 +179,26 @@ static void start_rpc(int target_port, grpc_status_code expected_status,
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
   op->data.send_initial_metadata.count = 0;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_CLOSE_FROM_CLIENT;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_INITIAL_METADATA;
   op->data.recv_initial_metadata.recv_initial_metadata = &initial_metadata_recv;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_STATUS_ON_CLIENT;
   op->data.recv_status_on_client.trailing_metadata = &trailing_metadata_recv;
   op->data.recv_status_on_client.status = &status;
   op->data.recv_status_on_client.status_details = &details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   error =
-      grpc_call_start_batch(state.call, ops, (size_t)(op - ops), tag(1), NULL);
+      grpc_call_start_batch(state.call, ops, (size_t)(op - ops), tag(1), nullptr);
 
   GPR_ASSERT(GRPC_CALL_OK == error);
 
@@ -206,7 +206,7 @@ static void start_rpc(int target_port, grpc_status_code expected_status,
   cq_verify(cqv);
 
   GPR_ASSERT(status == expected_status);
-  if (expected_detail != NULL) {
+  if (expected_detail != nullptr) {
     GPR_ASSERT(-1 != grpc_slice_slice(details, grpc_slice_from_static_string(
                                                    expected_detail)));
   }
@@ -224,7 +224,7 @@ static void cleanup_rpc(grpc_exec_ctx* exec_ctx) {
   grpc_call_unref(state.call);
   grpc_completion_queue_shutdown(state.cq);
   do {
-    ev = grpc_completion_queue_next(state.cq, n_sec_deadline(1), NULL);
+    ev = grpc_completion_queue_next(state.cq, n_sec_deadline(1), nullptr);
   } while (ev.type != GRPC_QUEUE_SHUTDOWN);
   grpc_completion_queue_destroy(state.cq);
   grpc_channel_destroy(state.channel);
@@ -262,7 +262,7 @@ static void poll_server_until_read_done(test_tcp_server* server,
   poll_args* pa = (poll_args*)gpr_malloc(sizeof(*pa));
   pa->server = server;
   pa->signal_when_done = signal_when_done;
-  gpr_thd_new(&id, actually_poll_server, pa, NULL);
+  gpr_thd_new(&id, actually_poll_server, pa, nullptr);
 }
 
 static void run_test(const char* response_payload,
@@ -331,7 +331,7 @@ int main(int argc, char** argv) {
 
   /* unparseable response */
   run_test(UNPARSEABLE_RESP, sizeof(UNPARSEABLE_RESP) - 1, GRPC_STATUS_UNKNOWN,
-           NULL);
+           nullptr);
 
   /* http1 response */
   run_test(HTTP1_RESP, sizeof(HTTP1_RESP) - 1, GRPC_STATUS_UNAVAILABLE,
diff --git a/test/core/end2end/connection_refused_test.cc b/test/core/end2end/connection_refused_test.cc
index cea06ae282..7fc36706f8 100644
--- a/test/core/end2end/connection_refused_test.cc
+++ b/test/core/end2end/connection_refused_test.cc
@@ -53,11 +53,11 @@ static void run_test(bool wait_for_ready, bool use_service_config) {
 
   grpc_metadata_array_init(&trailing_metadata_recv);
 
-  cq = grpc_completion_queue_create_for_next(NULL);
+  cq = grpc_completion_queue_create_for_next(nullptr);
   cqv = cq_verifier_create(cq);
 
   /* if using service config, create channel args */
-  grpc_channel_args* args = NULL;
+  grpc_channel_args* args = nullptr;
   if (use_service_config) {
     GPR_ASSERT(wait_for_ready);
     grpc_arg arg;
@@ -80,12 +80,12 @@ static void run_test(bool wait_for_ready, bool use_service_config) {
   char* addr;
   gpr_join_host_port(&addr, "127.0.0.1", port);
   gpr_log(GPR_INFO, "server: %s", addr);
-  chan = grpc_insecure_channel_create(addr, args, NULL);
+  chan = grpc_insecure_channel_create(addr, args, nullptr);
   grpc_slice host = grpc_slice_from_static_string("nonexistant");
   gpr_timespec deadline = grpc_timeout_seconds_to_deadline(2);
   call = grpc_channel_create_call(
-      chan, NULL, GRPC_PROPAGATE_DEFAULTS, cq,
-      grpc_slice_from_static_string("/service/method"), &host, deadline, NULL);
+      chan, nullptr, GRPC_PROPAGATE_DEFAULTS, cq,
+      grpc_slice_from_static_string("/service/method"), &host, deadline, nullptr);
 
   gpr_free(addr);
 
@@ -96,17 +96,17 @@ static void run_test(bool wait_for_ready, bool use_service_config) {
   op->flags = (wait_for_ready && !use_service_config)
                   ? GRPC_INITIAL_METADATA_WAIT_FOR_READY
                   : 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_STATUS_ON_CLIENT;
   op->data.recv_status_on_client.trailing_metadata = &trailing_metadata_recv;
   op->data.recv_status_on_client.status = &status;
   op->data.recv_status_on_client.status_details = &details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   GPR_ASSERT(GRPC_CALL_OK == grpc_call_start_batch(
-                                 call, ops, (size_t)(op - ops), tag(1), NULL));
+                                 call, ops, (size_t)(op - ops), tag(1), nullptr));
   /* verify that all tags get completed */
   CQ_EXPECT_COMPLETION(cqv, tag(1), 1);
   cq_verify(cqv);
@@ -119,7 +119,7 @@ static void run_test(bool wait_for_ready, bool use_service_config) {
 
   grpc_completion_queue_shutdown(cq);
   while (
-      grpc_completion_queue_next(cq, gpr_inf_future(GPR_CLOCK_REALTIME), NULL)
+      grpc_completion_queue_next(cq, gpr_inf_future(GPR_CLOCK_REALTIME), nullptr)
           .type != GRPC_QUEUE_SHUTDOWN)
     ;
   grpc_completion_queue_destroy(cq);
@@ -132,7 +132,7 @@ static void run_test(bool wait_for_ready, bool use_service_config) {
 
   {
     grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
-    if (args != NULL) grpc_channel_args_destroy(&exec_ctx, args);
+    if (args != nullptr) grpc_channel_args_destroy(&exec_ctx, args);
     grpc_exec_ctx_finish(&exec_ctx);
   }
 
diff --git a/test/core/end2end/cq_verifier.cc b/test/core/end2end/cq_verifier.cc
index fd5193f42c..d595124c00 100644
--- a/test/core/end2end/cq_verifier.cc
+++ b/test/core/end2end/cq_verifier.cc
@@ -64,7 +64,7 @@ struct cq_verifier {
 cq_verifier* cq_verifier_create(grpc_completion_queue* cq) {
   cq_verifier* v = (cq_verifier*)gpr_malloc(sizeof(cq_verifier));
   v->cq = cq;
-  v->first_expectation = NULL;
+  v->first_expectation = nullptr;
   return v;
 }
 
@@ -203,7 +203,7 @@ static void expectation_to_strvec(gpr_strvec* buf, expectation* e) {
 static void expectations_to_strvec(gpr_strvec* buf, cq_verifier* v) {
   expectation* e;
 
-  for (e = v->first_expectation; e != NULL; e = e->next) {
+  for (e = v->first_expectation; e != nullptr; e = e->next) {
     expectation_to_strvec(buf, e);
     gpr_strvec_add(buf, gpr_strdup("\n"));
   }
@@ -215,7 +215,7 @@ static void fail_no_event_received(cq_verifier* v) {
   gpr_strvec_init(&buf);
   gpr_strvec_add(&buf, gpr_strdup("no event received, but expected:\n"));
   expectations_to_strvec(&buf, v);
-  msg = gpr_strvec_flatten(&buf, NULL);
+  msg = gpr_strvec_flatten(&buf, nullptr);
   gpr_log(GPR_ERROR, "%s", msg);
   gpr_strvec_destroy(&buf);
   gpr_free(msg);
@@ -230,7 +230,7 @@ static void verify_matches(expectation* e, grpc_event* ev) {
         gpr_strvec expected;
         gpr_strvec_init(&expected);
         expectation_to_strvec(&expected, e);
-        char* s = gpr_strvec_flatten(&expected, NULL);
+        char* s = gpr_strvec_flatten(&expected, nullptr);
         gpr_strvec_destroy(&expected);
         gpr_log(GPR_ERROR, "actual success does not match expected: %s", s);
         gpr_free(s);
@@ -250,32 +250,32 @@ static void verify_matches(expectation* e, grpc_event* ev) {
 
 void cq_verify(cq_verifier* v) {
   const gpr_timespec deadline = grpc_timeout_seconds_to_deadline(10);
-  while (v->first_expectation != NULL) {
-    grpc_event ev = grpc_completion_queue_next(v->cq, deadline, NULL);
+  while (v->first_expectation != nullptr) {
+    grpc_event ev = grpc_completion_queue_next(v->cq, deadline, nullptr);
     if (ev.type == GRPC_QUEUE_TIMEOUT) {
       fail_no_event_received(v);
       break;
     }
     expectation* e;
-    expectation* prev = NULL;
-    for (e = v->first_expectation; e != NULL; e = e->next) {
+    expectation* prev = nullptr;
+    for (e = v->first_expectation; e != nullptr; e = e->next) {
       if (e->tag == ev.tag) {
         verify_matches(e, &ev);
         if (e == v->first_expectation) v->first_expectation = e->next;
-        if (prev != NULL) prev->next = e->next;
+        if (prev != nullptr) prev->next = e->next;
         gpr_free(e);
         break;
       }
       prev = e;
     }
-    if (e == NULL) {
+    if (e == nullptr) {
       char* s = grpc_event_string(&ev);
       gpr_log(GPR_ERROR, "cq returned unexpected event: %s", s);
       gpr_free(s);
       gpr_strvec expectations;
       gpr_strvec_init(&expectations);
       expectations_to_strvec(&expectations, v);
-      s = gpr_strvec_flatten(&expectations, NULL);
+      s = gpr_strvec_flatten(&expectations, nullptr);
       gpr_strvec_destroy(&expectations);
       gpr_log(GPR_ERROR, "expected tags:\n%s", s);
       gpr_free(s);
@@ -290,9 +290,9 @@ void cq_verify_empty_timeout(cq_verifier* v, int timeout_sec) {
                    gpr_time_from_seconds(timeout_sec, GPR_TIMESPAN));
   grpc_event ev;
 
-  GPR_ASSERT(v->first_expectation == NULL && "expectation queue must be empty");
+  GPR_ASSERT(v->first_expectation == nullptr && "expectation queue must be empty");
 
-  ev = grpc_completion_queue_next(v->cq, deadline, NULL);
+  ev = grpc_completion_queue_next(v->cq, deadline, nullptr);
   if (ev.type != GRPC_QUEUE_TIMEOUT) {
     char* s = grpc_event_string(&ev);
     gpr_log(GPR_ERROR, "unexpected event (expected nothing): %s", s);
diff --git a/test/core/end2end/cq_verifier_native.cc b/test/core/end2end/cq_verifier_native.cc
index a0a7c832e5..e93956b188 100644
--- a/test/core/end2end/cq_verifier_native.cc
+++ b/test/core/end2end/cq_verifier_native.cc
@@ -19,6 +19,8 @@
 /* This check is for testing only. */
 #ifndef GRPC_UV
 
+#include <grpc/support/alloc.h>
+
 #include "test/core/end2end/cq_verifier_internal.h"
 
 /* the verifier itself */
@@ -27,13 +29,12 @@ struct cq_verifier {
   grpc_completion_queue* cq;
   /* start of expectation list */
   expectation* first_expectation;
-  uv_timer_t timer;
 };
 
 cq_verifier* cq_verifier_create(grpc_completion_queue* cq) {
   cq_verifier* v = static_cast<cq_verifier*>(gpr_malloc(sizeof(cq_verifier)));
   v->cq = cq;
-  cq_verifier_set_first_expectation(v, NULL);
+  cq_verifier_set_first_expectation(v, nullptr);
   return v;
 }
 
@@ -53,7 +54,7 @@ void cq_verifier_set_first_expectation(cq_verifier* v, expectation* e) {
 grpc_event cq_verifier_next_event(cq_verifier* v, int timeout_seconds) {
   const gpr_timespec deadline =
       grpc_timeout_seconds_to_deadline(timeout_seconds);
-  return grpc_completion_queue_next(v->cq, deadline, NULL);
+  return grpc_completion_queue_next(v->cq, deadline, nullptr);
 }
 
 #endif /* GRPC_UV */
diff --git a/test/core/end2end/dualstack_socket_test.cc b/test/core/end2end/dualstack_socket_test.cc
index 1e02116e4c..2c7a6cfbbc 100644
--- a/test/core/end2end/dualstack_socket_test.cc
+++ b/test/core/end2end/dualstack_socket_test.cc
@@ -48,7 +48,7 @@ static gpr_timespec ms_from_now(int ms) {
 static void drain_cq(grpc_completion_queue* cq) {
   grpc_event ev;
   do {
-    ev = grpc_completion_queue_next(cq, ms_from_now(5000), NULL);
+    ev = grpc_completion_queue_next(cq, ms_from_now(5000), nullptr);
   } while (ev.type != GRPC_QUEUE_SHUTDOWN);
 }
 
@@ -93,9 +93,9 @@ void test_connect(const char* server_host, const char* client_host, int port,
   grpc_call_details_init(&call_details);
 
   /* Create server. */
-  cq = grpc_completion_queue_create_for_next(NULL);
-  server = grpc_server_create(NULL, NULL);
-  grpc_server_register_completion_queue(server, cq, NULL);
+  cq = grpc_completion_queue_create_for_next(nullptr);
+  server = grpc_server_create(nullptr, nullptr);
+  grpc_server_register_completion_queue(server, cq, nullptr);
   GPR_ASSERT((got_port = grpc_server_add_insecure_http2_port(
                   server, server_hostport)) > 0);
   if (port == 0) {
@@ -126,7 +126,7 @@ void test_connect(const char* server_host, const char* client_host, int port,
       gpr_free(uri_part_str);
     }
     client_hostport = gpr_strjoin_sep((const char**)hosts_with_port,
-                                      uri_parts.count, ",", NULL);
+                                      uri_parts.count, ",", nullptr);
     for (i = 0; i < uri_parts.count; i++) {
       gpr_free(hosts_with_port[i]);
     }
@@ -136,7 +136,7 @@ void test_connect(const char* server_host, const char* client_host, int port,
   } else {
     gpr_join_host_port(&client_hostport, client_host, port);
   }
-  client = grpc_insecure_channel_create(client_hostport, NULL, NULL);
+  client = grpc_insecure_channel_create(client_hostport, nullptr, nullptr);
 
   gpr_log(GPR_INFO, "Testing with server=%s client=%s (expecting %s)",
           server_hostport, client_hostport, expect_ok ? "success" : "failure");
@@ -155,9 +155,9 @@ void test_connect(const char* server_host, const char* client_host, int port,
 
   /* Send a trivial request. */
   grpc_slice host = grpc_slice_from_static_string("foo.test.google.fr");
-  c = grpc_channel_create_call(client, NULL, GRPC_PROPAGATE_DEFAULTS, cq,
+  c = grpc_channel_create_call(client, nullptr, GRPC_PROPAGATE_DEFAULTS, cq,
                                grpc_slice_from_static_string("/foo"), &host,
-                               deadline, NULL);
+                               deadline, nullptr);
   GPR_ASSERT(c);
 
   memset(ops, 0, sizeof(ops));
@@ -165,25 +165,25 @@ void test_connect(const char* server_host, const char* client_host, int port,
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
   op->data.send_initial_metadata.count = 0;
   op->flags = expect_ok ? GRPC_INITIAL_METADATA_WAIT_FOR_READY : 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_CLOSE_FROM_CLIENT;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_INITIAL_METADATA;
   op->data.recv_initial_metadata.recv_initial_metadata = &initial_metadata_recv;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_STATUS_ON_CLIENT;
   op->data.recv_status_on_client.trailing_metadata = &trailing_metadata_recv;
   op->data.recv_status_on_client.status = &status;
   op->data.recv_status_on_client.status_details = &details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), NULL);
+  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   if (expect_ok) {
@@ -211,7 +211,7 @@ void test_connect(const char* server_host, const char* client_host, int port,
     op->data.recv_close_on_server.cancelled = &was_cancelled;
     op->flags = 0;
     op++;
-    error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(102), NULL);
+    error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(102), nullptr);
     GPR_ASSERT(GRPC_CALL_OK == error);
 
     CQ_EXPECT_COMPLETION(cqv, tag(102), 1);
@@ -246,11 +246,11 @@ void test_connect(const char* server_host, const char* client_host, int port,
   grpc_channel_destroy(client);
 
   /* Destroy server. */
-  shutdown_cq = grpc_completion_queue_create_for_pluck(NULL);
+  shutdown_cq = grpc_completion_queue_create_for_pluck(nullptr);
   grpc_server_shutdown_and_notify(server, shutdown_cq, tag(1000));
   GPR_ASSERT(grpc_completion_queue_pluck(shutdown_cq, tag(1000),
                                          grpc_timeout_seconds_to_deadline(5),
-                                         NULL)
+                                         nullptr)
                  .type == GRPC_OP_COMPLETE);
   grpc_server_destroy(server);
   grpc_completion_queue_destroy(shutdown_cq);
@@ -270,10 +270,10 @@ void test_connect(const char* server_host, const char* client_host, int port,
 }
 
 int external_dns_works(const char* host) {
-  grpc_resolved_addresses* res = NULL;
+  grpc_resolved_addresses* res = nullptr;
   grpc_error* error = grpc_blocking_resolve_address(host, "80", &res);
   GRPC_ERROR_UNREF(error);
-  if (res != NULL) {
+  if (res != nullptr) {
     grpc_resolved_addresses_destroy(res);
     return 1;
   }
diff --git a/test/core/end2end/end2end_test_utils.cc b/test/core/end2end/end2end_test_utils.cc
index 35f086a7f6..51d2730f0e 100644
--- a/test/core/end2end/end2end_test_utils.cc
+++ b/test/core/end2end/end2end_test_utils.cc
@@ -27,19 +27,19 @@ const char* get_host_override_string(const char* str,
   if (config.feature_mask & FEATURE_MASK_SUPPORTS_AUTHORITY_HEADER) {
     return str;
   } else {
-    return NULL;
+    return nullptr;
   }
 }
 
 const grpc_slice* get_host_override_slice(const char* str,
                                           grpc_end2end_test_config config) {
   const char* r = get_host_override_string(str, config);
-  if (r != NULL) {
+  if (r != nullptr) {
     static grpc_slice ret;
     ret = grpc_slice_from_static_string(r);
     return &ret;
   }
-  return NULL;
+  return nullptr;
 }
 
 void validate_host_override_string(const char* pattern, grpc_slice str,
diff --git a/test/core/end2end/fixtures/h2_census.cc b/test/core/end2end/fixtures/h2_census.cc
index 4213140f4a..89d992cf52 100644
--- a/test/core/end2end/fixtures/h2_census.cc
+++ b/test/core/end2end/fixtures/h2_census.cc
@@ -51,8 +51,8 @@ static grpc_end2end_test_fixture chttp2_create_fixture_fullstack(
   gpr_join_host_port(&ffd->localaddr, "localhost", port);
 
   f.fixture_data = ffd;
-  f.cq = grpc_completion_queue_create_for_next(NULL);
-  f.shutdown_cq = grpc_completion_queue_create_for_pluck(NULL);
+  f.cq = grpc_completion_queue_create_for_next(nullptr);
+  f.shutdown_cq = grpc_completion_queue_create_for_pluck(nullptr);
 
   return f;
 }
@@ -71,7 +71,7 @@ void chttp2_init_client_fullstack(grpc_end2end_test_fixture* f,
       static_cast<fullstack_fixture_data*>(f->fixture_data);
   grpc_arg arg = make_census_enable_arg();
   client_args = grpc_channel_args_copy_and_add(client_args, &arg, 1);
-  f->client = grpc_insecure_channel_create(ffd->localaddr, client_args, NULL);
+  f->client = grpc_insecure_channel_create(ffd->localaddr, client_args, nullptr);
   GPR_ASSERT(f->client);
   {
     grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
@@ -89,13 +89,13 @@ void chttp2_init_server_fullstack(grpc_end2end_test_fixture* f,
     grpc_server_destroy(f->server);
   }
   server_args = grpc_channel_args_copy_and_add(server_args, &arg, 1);
-  f->server = grpc_server_create(server_args, NULL);
+  f->server = grpc_server_create(server_args, nullptr);
   {
     grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
     grpc_channel_args_destroy(&exec_ctx, server_args);
     grpc_exec_ctx_finish(&exec_ctx);
   }
-  grpc_server_register_completion_queue(f->server, f->cq, NULL);
+  grpc_server_register_completion_queue(f->server, f->cq, nullptr);
   GPR_ASSERT(grpc_server_add_insecure_http2_port(f->server, ffd->localaddr));
   grpc_server_start(f->server);
 }
diff --git a/test/core/end2end/fixtures/h2_compress.cc b/test/core/end2end/fixtures/h2_compress.cc
index 64e028b950..fbf4d2061b 100644
--- a/test/core/end2end/fixtures/h2_compress.cc
+++ b/test/core/end2end/fixtures/h2_compress.cc
@@ -55,8 +55,8 @@ static grpc_end2end_test_fixture chttp2_create_fixture_fullstack_compression(
 
   memset(&f, 0, sizeof(f));
   f.fixture_data = ffd;
-  f.cq = grpc_completion_queue_create_for_next(NULL);
-  f.shutdown_cq = grpc_completion_queue_create_for_pluck(NULL);
+  f.cq = grpc_completion_queue_create_for_next(nullptr);
+  f.shutdown_cq = grpc_completion_queue_create_for_pluck(nullptr);
 
   return f;
 }
@@ -65,7 +65,7 @@ void chttp2_init_client_fullstack_compression(grpc_end2end_test_fixture* f,
                                               grpc_channel_args* client_args) {
   fullstack_compression_fixture_data* ffd =
       static_cast<fullstack_compression_fixture_data*>(f->fixture_data);
-  if (ffd->client_args_compression != NULL) {
+  if (ffd->client_args_compression != nullptr) {
     grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
     grpc_channel_args_destroy(&exec_ctx, ffd->client_args_compression);
     grpc_exec_ctx_finish(&exec_ctx);
@@ -73,14 +73,14 @@ void chttp2_init_client_fullstack_compression(grpc_end2end_test_fixture* f,
   ffd->client_args_compression = grpc_channel_args_set_compression_algorithm(
       client_args, GRPC_COMPRESS_GZIP);
   f->client = grpc_insecure_channel_create(ffd->localaddr,
-                                           ffd->client_args_compression, NULL);
+                                           ffd->client_args_compression, nullptr);
 }
 
 void chttp2_init_server_fullstack_compression(grpc_end2end_test_fixture* f,
                                               grpc_channel_args* server_args) {
   fullstack_compression_fixture_data* ffd =
       static_cast<fullstack_compression_fixture_data*>(f->fixture_data);
-  if (ffd->server_args_compression != NULL) {
+  if (ffd->server_args_compression != nullptr) {
     grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
     grpc_channel_args_destroy(&exec_ctx, ffd->server_args_compression);
     grpc_exec_ctx_finish(&exec_ctx);
@@ -90,8 +90,8 @@ void chttp2_init_server_fullstack_compression(grpc_end2end_test_fixture* f,
   if (f->server) {
     grpc_server_destroy(f->server);
   }
-  f->server = grpc_server_create(ffd->server_args_compression, NULL);
-  grpc_server_register_completion_queue(f->server, f->cq, NULL);
+  f->server = grpc_server_create(ffd->server_args_compression, nullptr);
+  grpc_server_register_completion_queue(f->server, f->cq, nullptr);
   GPR_ASSERT(grpc_server_add_insecure_http2_port(f->server, ffd->localaddr));
   grpc_server_start(f->server);
 }
diff --git a/test/core/end2end/fixtures/h2_fakesec.cc b/test/core/end2end/fixtures/h2_fakesec.cc
index fbf2f49729..570d040976 100644
--- a/test/core/end2end/fixtures/h2_fakesec.cc
+++ b/test/core/end2end/fixtures/h2_fakesec.cc
@@ -46,8 +46,8 @@ static grpc_end2end_test_fixture chttp2_create_fixture_secure_fullstack(
   gpr_join_host_port(&ffd->localaddr, "localhost", port);
 
   f.fixture_data = ffd;
-  f.cq = grpc_completion_queue_create_for_next(NULL);
-  f.shutdown_cq = grpc_completion_queue_create_for_pluck(NULL);
+  f.cq = grpc_completion_queue_create_for_next(nullptr);
+  f.shutdown_cq = grpc_completion_queue_create_for_pluck(nullptr);
 
   return f;
 }
@@ -56,8 +56,8 @@ static void process_auth_failure(void* state, grpc_auth_context* ctx,
                                  const grpc_metadata* md, size_t md_count,
                                  grpc_process_auth_metadata_done_cb cb,
                                  void* user_data) {
-  GPR_ASSERT(state == NULL);
-  cb(user_data, NULL, 0, NULL, 0, GRPC_STATUS_UNAUTHENTICATED, NULL);
+  GPR_ASSERT(state == nullptr);
+  cb(user_data, nullptr, 0, nullptr, 0, GRPC_STATUS_UNAUTHENTICATED, nullptr);
 }
 
 static void chttp2_init_client_secure_fullstack(
@@ -66,8 +66,8 @@ static void chttp2_init_client_secure_fullstack(
   fullstack_secure_fixture_data* ffd =
       static_cast<fullstack_secure_fixture_data*>(f->fixture_data);
   f->client =
-      grpc_secure_channel_create(creds, ffd->localaddr, client_args, NULL);
-  GPR_ASSERT(f->client != NULL);
+      grpc_secure_channel_create(creds, ffd->localaddr, client_args, nullptr);
+  GPR_ASSERT(f->client != nullptr);
   grpc_channel_credentials_release(creds);
 }
 
@@ -79,8 +79,8 @@ static void chttp2_init_server_secure_fullstack(
   if (f->server) {
     grpc_server_destroy(f->server);
   }
-  f->server = grpc_server_create(server_args, NULL);
-  grpc_server_register_completion_queue(f->server, f->cq, NULL);
+  f->server = grpc_server_create(server_args, nullptr);
+  grpc_server_register_completion_queue(f->server, f->cq, nullptr);
   GPR_ASSERT(grpc_server_add_secure_http2_port(f->server, ffd->localaddr,
                                                server_creds));
   grpc_server_credentials_release(server_creds);
@@ -103,7 +103,7 @@ static void chttp2_init_client_fake_secure_fullstack(
 
 static int fail_server_auth_check(grpc_channel_args* server_args) {
   size_t i;
-  if (server_args == NULL) return 0;
+  if (server_args == nullptr) return 0;
   for (i = 0; i < server_args->num_args; i++) {
     if (strcmp(server_args->args[i].key, FAIL_AUTH_CHECK_SERVER_ARG_NAME) ==
         0) {
@@ -118,7 +118,7 @@ static void chttp2_init_server_fake_secure_fullstack(
   grpc_server_credentials* fake_ts_creds =
       grpc_fake_transport_security_server_credentials_create();
   if (fail_server_auth_check(server_args)) {
-    grpc_auth_metadata_processor processor = {process_auth_failure, NULL, NULL};
+    grpc_auth_metadata_processor processor = {process_auth_failure, nullptr, nullptr};
     grpc_server_credentials_set_auth_metadata_processor(fake_ts_creds,
                                                         processor);
   }
diff --git a/test/core/end2end/fixtures/h2_fd.cc b/test/core/end2end/fixtures/h2_fd.cc
index 7005b969a0..97f4b71bf0 100644
--- a/test/core/end2end/fixtures/h2_fd.cc
+++ b/test/core/end2end/fixtures/h2_fd.cc
@@ -58,8 +58,8 @@ static grpc_end2end_test_fixture chttp2_create_fixture_socketpair(
   grpc_end2end_test_fixture f;
   memset(&f, 0, sizeof(f));
   f.fixture_data = fixture_data;
-  f.cq = grpc_completion_queue_create_for_next(NULL);
-  f.shutdown_cq = grpc_completion_queue_create_for_pluck(NULL);
+  f.cq = grpc_completion_queue_create_for_next(nullptr);
+  f.shutdown_cq = grpc_completion_queue_create_for_pluck(nullptr);
 
   create_sockets(fixture_data->fd_pair);
 
@@ -84,12 +84,12 @@ static void chttp2_init_server_socketpair(grpc_end2end_test_fixture* f,
   grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
   sp_fixture_data* sfd = static_cast<sp_fixture_data*>(f->fixture_data);
   GPR_ASSERT(!f->server);
-  f->server = grpc_server_create(server_args, NULL);
+  f->server = grpc_server_create(server_args, nullptr);
   GPR_ASSERT(f->server);
-  grpc_server_register_completion_queue(f->server, f->cq, NULL);
+  grpc_server_register_completion_queue(f->server, f->cq, nullptr);
   grpc_server_start(f->server);
 
-  grpc_server_add_insecure_channel_from_fd(f->server, NULL, sfd->fd_pair[1]);
+  grpc_server_add_insecure_channel_from_fd(f->server, nullptr, sfd->fd_pair[1]);
 
   grpc_exec_ctx_finish(&exec_ctx);
 }
diff --git a/test/core/end2end/fixtures/h2_full+pipe.cc b/test/core/end2end/fixtures/h2_full+pipe.cc
index 0dd650b8e0..306c85871b 100644
--- a/test/core/end2end/fixtures/h2_full+pipe.cc
+++ b/test/core/end2end/fixtures/h2_full+pipe.cc
@@ -56,8 +56,8 @@ static grpc_end2end_test_fixture chttp2_create_fixture_fullstack(
   gpr_join_host_port(&ffd->localaddr, "localhost", port);
 
   f.fixture_data = ffd;
-  f.cq = grpc_completion_queue_create_for_next(NULL);
-  f.shutdown_cq = grpc_completion_queue_create_for_pluck(NULL);
+  f.cq = grpc_completion_queue_create_for_next(nullptr);
+  f.shutdown_cq = grpc_completion_queue_create_for_pluck(nullptr);
 
   return f;
 }
@@ -66,7 +66,7 @@ void chttp2_init_client_fullstack(grpc_end2end_test_fixture* f,
                                   grpc_channel_args* client_args) {
   fullstack_fixture_data* ffd =
       static_cast<fullstack_fixture_data*>(f->fixture_data);
-  f->client = grpc_insecure_channel_create(ffd->localaddr, client_args, NULL);
+  f->client = grpc_insecure_channel_create(ffd->localaddr, client_args, nullptr);
   GPR_ASSERT(f->client);
 }
 
@@ -77,8 +77,8 @@ void chttp2_init_server_fullstack(grpc_end2end_test_fixture* f,
   if (f->server) {
     grpc_server_destroy(f->server);
   }
-  f->server = grpc_server_create(server_args, NULL);
-  grpc_server_register_completion_queue(f->server, f->cq, NULL);
+  f->server = grpc_server_create(server_args, nullptr);
+  grpc_server_register_completion_queue(f->server, f->cq, nullptr);
   GPR_ASSERT(grpc_server_add_insecure_http2_port(f->server, ffd->localaddr));
   grpc_server_start(f->server);
 }
diff --git a/test/core/end2end/fixtures/h2_full+trace.cc b/test/core/end2end/fixtures/h2_full+trace.cc
index 21372c6dee..589bf1d7e4 100644
--- a/test/core/end2end/fixtures/h2_full+trace.cc
+++ b/test/core/end2end/fixtures/h2_full+trace.cc
@@ -56,8 +56,8 @@ static grpc_end2end_test_fixture chttp2_create_fixture_fullstack(
   gpr_join_host_port(&ffd->localaddr, "localhost", port);
 
   f.fixture_data = ffd;
-  f.cq = grpc_completion_queue_create_for_next(NULL);
-  f.shutdown_cq = grpc_completion_queue_create_for_pluck(NULL);
+  f.cq = grpc_completion_queue_create_for_next(nullptr);
+  f.shutdown_cq = grpc_completion_queue_create_for_pluck(nullptr);
 
   return f;
 }
@@ -66,7 +66,7 @@ void chttp2_init_client_fullstack(grpc_end2end_test_fixture* f,
                                   grpc_channel_args* client_args) {
   fullstack_fixture_data* ffd =
       static_cast<fullstack_fixture_data*>(f->fixture_data);
-  f->client = grpc_insecure_channel_create(ffd->localaddr, client_args, NULL);
+  f->client = grpc_insecure_channel_create(ffd->localaddr, client_args, nullptr);
   GPR_ASSERT(f->client);
 }
 
@@ -77,8 +77,8 @@ void chttp2_init_server_fullstack(grpc_end2end_test_fixture* f,
   if (f->server) {
     grpc_server_destroy(f->server);
   }
-  f->server = grpc_server_create(server_args, NULL);
-  grpc_server_register_completion_queue(f->server, f->cq, NULL);
+  f->server = grpc_server_create(server_args, nullptr);
+  grpc_server_register_completion_queue(f->server, f->cq, nullptr);
   GPR_ASSERT(grpc_server_add_insecure_http2_port(f->server, ffd->localaddr));
   grpc_server_start(f->server);
 }
diff --git a/test/core/end2end/fixtures/h2_full+workarounds.cc b/test/core/end2end/fixtures/h2_full+workarounds.cc
index ebffe2125c..ffe2623c44 100644
--- a/test/core/end2end/fixtures/h2_full+workarounds.cc
+++ b/test/core/end2end/fixtures/h2_full+workarounds.cc
@@ -54,8 +54,8 @@ static grpc_end2end_test_fixture chttp2_create_fixture_fullstack(
   gpr_join_host_port(&ffd->localaddr, "localhost", port);
 
   f.fixture_data = ffd;
-  f.cq = grpc_completion_queue_create_for_next(NULL);
-  f.shutdown_cq = grpc_completion_queue_create_for_pluck(NULL);
+  f.cq = grpc_completion_queue_create_for_next(nullptr);
+  f.shutdown_cq = grpc_completion_queue_create_for_pluck(nullptr);
 
   return f;
 }
@@ -64,7 +64,7 @@ void chttp2_init_client_fullstack(grpc_end2end_test_fixture* f,
                                   grpc_channel_args* client_args) {
   fullstack_fixture_data* ffd =
       static_cast<fullstack_fixture_data*>(f->fixture_data);
-  f->client = grpc_insecure_channel_create(ffd->localaddr, client_args, NULL);
+  f->client = grpc_insecure_channel_create(ffd->localaddr, client_args, nullptr);
   GPR_ASSERT(f->client);
 }
 
@@ -85,8 +85,8 @@ void chttp2_init_server_fullstack(grpc_end2end_test_fixture* f,
   if (f->server) {
     grpc_server_destroy(f->server);
   }
-  f->server = grpc_server_create(server_args_new, NULL);
-  grpc_server_register_completion_queue(f->server, f->cq, NULL);
+  f->server = grpc_server_create(server_args_new, nullptr);
+  grpc_server_register_completion_queue(f->server, f->cq, nullptr);
   GPR_ASSERT(grpc_server_add_insecure_http2_port(f->server, ffd->localaddr));
   grpc_server_start(f->server);
   grpc_channel_args_destroy(&exec_ctx, server_args_new);
diff --git a/test/core/end2end/fixtures/h2_full.cc b/test/core/end2end/fixtures/h2_full.cc
index 895af67930..c0a9524cc6 100644
--- a/test/core/end2end/fixtures/h2_full.cc
+++ b/test/core/end2end/fixtures/h2_full.cc
@@ -50,8 +50,8 @@ static grpc_end2end_test_fixture chttp2_create_fixture_fullstack(
   gpr_join_host_port(&ffd->localaddr, "localhost", port);
 
   f.fixture_data = ffd;
-  f.cq = grpc_completion_queue_create_for_next(NULL);
-  f.shutdown_cq = grpc_completion_queue_create_for_pluck(NULL);
+  f.cq = grpc_completion_queue_create_for_next(nullptr);
+  f.shutdown_cq = grpc_completion_queue_create_for_pluck(nullptr);
 
   return f;
 }
@@ -60,7 +60,7 @@ void chttp2_init_client_fullstack(grpc_end2end_test_fixture* f,
                                   grpc_channel_args* client_args) {
   fullstack_fixture_data* ffd =
       static_cast<fullstack_fixture_data*>(f->fixture_data);
-  f->client = grpc_insecure_channel_create(ffd->localaddr, client_args, NULL);
+  f->client = grpc_insecure_channel_create(ffd->localaddr, client_args, nullptr);
   GPR_ASSERT(f->client);
 }
 
@@ -71,8 +71,8 @@ void chttp2_init_server_fullstack(grpc_end2end_test_fixture* f,
   if (f->server) {
     grpc_server_destroy(f->server);
   }
-  f->server = grpc_server_create(server_args, NULL);
-  grpc_server_register_completion_queue(f->server, f->cq, NULL);
+  f->server = grpc_server_create(server_args, nullptr);
+  grpc_server_register_completion_queue(f->server, f->cq, nullptr);
   GPR_ASSERT(grpc_server_add_insecure_http2_port(f->server, ffd->localaddr));
   grpc_server_start(f->server);
 }
diff --git a/test/core/end2end/fixtures/h2_http_proxy.cc b/test/core/end2end/fixtures/h2_http_proxy.cc
index a67ce82064..45f6cb56ac 100644
--- a/test/core/end2end/fixtures/h2_http_proxy.cc
+++ b/test/core/end2end/fixtures/h2_http_proxy.cc
@@ -57,8 +57,8 @@ static grpc_end2end_test_fixture chttp2_create_fixture_fullstack(
   ffd->proxy = grpc_end2end_http_proxy_create(client_args);
 
   f.fixture_data = ffd;
-  f.cq = grpc_completion_queue_create_for_next(NULL);
-  f.shutdown_cq = grpc_completion_queue_create_for_pluck(NULL);
+  f.cq = grpc_completion_queue_create_for_next(nullptr);
+  f.shutdown_cq = grpc_completion_queue_create_for_pluck(nullptr);
 
   return f;
 }
@@ -72,7 +72,7 @@ void chttp2_init_client_fullstack(grpc_end2end_test_fixture* f,
   /* If testing for proxy auth, add credentials to proxy uri */
   const grpc_arg* proxy_auth_arg =
       grpc_channel_args_find(client_args, GRPC_ARG_HTTP_PROXY_AUTH_CREDS);
-  if (proxy_auth_arg == NULL || proxy_auth_arg->type != GRPC_ARG_STRING) {
+  if (proxy_auth_arg == nullptr || proxy_auth_arg->type != GRPC_ARG_STRING) {
     gpr_asprintf(&proxy_uri, "http://%s",
                  grpc_end2end_http_proxy_get_proxy_name(ffd->proxy));
   } else {
@@ -81,7 +81,7 @@ void chttp2_init_client_fullstack(grpc_end2end_test_fixture* f,
   }
   gpr_setenv("http_proxy", proxy_uri);
   gpr_free(proxy_uri);
-  f->client = grpc_insecure_channel_create(ffd->server_addr, client_args, NULL);
+  f->client = grpc_insecure_channel_create(ffd->server_addr, client_args, nullptr);
   GPR_ASSERT(f->client);
 }
 
@@ -92,8 +92,8 @@ void chttp2_init_server_fullstack(grpc_end2end_test_fixture* f,
   if (f->server) {
     grpc_server_destroy(f->server);
   }
-  f->server = grpc_server_create(server_args, NULL);
-  grpc_server_register_completion_queue(f->server, f->cq, NULL);
+  f->server = grpc_server_create(server_args, nullptr);
+  grpc_server_register_completion_queue(f->server, f->cq, nullptr);
   GPR_ASSERT(grpc_server_add_insecure_http2_port(f->server, ffd->server_addr));
   grpc_server_start(f->server);
 }
diff --git a/test/core/end2end/fixtures/h2_load_reporting.cc b/test/core/end2end/fixtures/h2_load_reporting.cc
index b402fc5620..c0aa8ebdce 100644
--- a/test/core/end2end/fixtures/h2_load_reporting.cc
+++ b/test/core/end2end/fixtures/h2_load_reporting.cc
@@ -52,8 +52,8 @@ static grpc_end2end_test_fixture chttp2_create_fixture_load_reporting(
   gpr_join_host_port(&ffd->localaddr, "localhost", port);
 
   f.fixture_data = ffd;
-  f.cq = grpc_completion_queue_create_for_next(NULL);
-  f.shutdown_cq = grpc_completion_queue_create_for_pluck(NULL);
+  f.cq = grpc_completion_queue_create_for_next(nullptr);
+  f.shutdown_cq = grpc_completion_queue_create_for_pluck(nullptr);
 
   return f;
 }
@@ -62,7 +62,7 @@ void chttp2_init_client_load_reporting(grpc_end2end_test_fixture* f,
                                        grpc_channel_args* client_args) {
   load_reporting_fixture_data* ffd =
       static_cast<load_reporting_fixture_data*>(f->fixture_data);
-  f->client = grpc_insecure_channel_create(ffd->localaddr, client_args, NULL);
+  f->client = grpc_insecure_channel_create(ffd->localaddr, client_args, nullptr);
   GPR_ASSERT(f->client);
 }
 
@@ -75,13 +75,13 @@ void chttp2_init_server_load_reporting(grpc_end2end_test_fixture* f,
     grpc_server_destroy(f->server);
   }
   server_args = grpc_channel_args_copy_and_add(server_args, &arg, 1);
-  f->server = grpc_server_create(server_args, NULL);
+  f->server = grpc_server_create(server_args, nullptr);
   {
     grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
     grpc_channel_args_destroy(&exec_ctx, server_args);
     grpc_exec_ctx_finish(&exec_ctx);
   }
-  grpc_server_register_completion_queue(f->server, f->cq, NULL);
+  grpc_server_register_completion_queue(f->server, f->cq, nullptr);
   GPR_ASSERT(grpc_server_add_insecure_http2_port(f->server, ffd->localaddr));
   grpc_server_start(f->server);
 }
diff --git a/test/core/end2end/fixtures/h2_oauth2.cc b/test/core/end2end/fixtures/h2_oauth2.cc
index 88e590a15f..474a1b4b9e 100644
--- a/test/core/end2end/fixtures/h2_oauth2.cc
+++ b/test/core/end2end/fixtures/h2_oauth2.cc
@@ -49,7 +49,7 @@ static const grpc_metadata* find_metadata(const grpc_metadata* md,
       return &md[i];
     }
   }
-  return NULL;
+  return nullptr;
 }
 
 typedef struct {
@@ -64,15 +64,15 @@ static void process_oauth2_success(void* state, grpc_auth_context* ctx,
       find_metadata(md, md_count, "authorization", oauth2_md);
   test_processor_state* s;
 
-  GPR_ASSERT(state != NULL);
+  GPR_ASSERT(state != nullptr);
   s = (test_processor_state*)state;
   GPR_ASSERT(s->pseudo_refcount == 1);
-  GPR_ASSERT(oauth2 != NULL);
+  GPR_ASSERT(oauth2 != nullptr);
   grpc_auth_context_add_cstring_property(ctx, client_identity_property_name,
                                          client_identity);
   GPR_ASSERT(grpc_auth_context_set_peer_identity_property_name(
                  ctx, client_identity_property_name) == 1);
-  cb(user_data, oauth2, 1, NULL, 0, GRPC_STATUS_OK, NULL);
+  cb(user_data, oauth2, 1, nullptr, 0, GRPC_STATUS_OK, nullptr);
 }
 
 static void process_oauth2_failure(void* state, grpc_auth_context* ctx,
@@ -82,11 +82,11 @@ static void process_oauth2_failure(void* state, grpc_auth_context* ctx,
   const grpc_metadata* oauth2 =
       find_metadata(md, md_count, "authorization", oauth2_md);
   test_processor_state* s;
-  GPR_ASSERT(state != NULL);
+  GPR_ASSERT(state != nullptr);
   s = (test_processor_state*)state;
   GPR_ASSERT(s->pseudo_refcount == 1);
-  GPR_ASSERT(oauth2 != NULL);
-  cb(user_data, oauth2, 1, NULL, 0, GRPC_STATUS_UNAUTHENTICATED, NULL);
+  GPR_ASSERT(oauth2 != nullptr);
+  cb(user_data, oauth2, 1, nullptr, 0, GRPC_STATUS_UNAUTHENTICATED, nullptr);
 }
 
 static grpc_end2end_test_fixture chttp2_create_fixture_secure_fullstack(
@@ -101,8 +101,8 @@ static grpc_end2end_test_fixture chttp2_create_fixture_secure_fullstack(
   gpr_join_host_port(&ffd->localaddr, "localhost", port);
 
   f.fixture_data = ffd;
-  f.cq = grpc_completion_queue_create_for_next(NULL);
-  f.shutdown_cq = grpc_completion_queue_create_for_pluck(NULL);
+  f.cq = grpc_completion_queue_create_for_next(nullptr);
+  f.shutdown_cq = grpc_completion_queue_create_for_pluck(nullptr);
 
   return f;
 }
@@ -113,8 +113,8 @@ static void chttp2_init_client_secure_fullstack(
   fullstack_secure_fixture_data* ffd =
       static_cast<fullstack_secure_fixture_data*>(f->fixture_data);
   f->client =
-      grpc_secure_channel_create(creds, ffd->localaddr, client_args, NULL);
-  GPR_ASSERT(f->client != NULL);
+      grpc_secure_channel_create(creds, ffd->localaddr, client_args, nullptr);
+  GPR_ASSERT(f->client != nullptr);
   grpc_channel_credentials_release(creds);
 }
 
@@ -126,8 +126,8 @@ static void chttp2_init_server_secure_fullstack(
   if (f->server) {
     grpc_server_destroy(f->server);
   }
-  f->server = grpc_server_create(server_args, NULL);
-  grpc_server_register_completion_queue(f->server, f->cq, NULL);
+  f->server = grpc_server_create(server_args, nullptr);
+  grpc_server_register_completion_queue(f->server, f->cq, nullptr);
   GPR_ASSERT(grpc_server_add_secure_http2_port(f->server, ffd->localaddr,
                                                server_creds));
   grpc_server_credentials_release(server_creds);
@@ -145,11 +145,11 @@ static void chttp2_init_client_simple_ssl_with_oauth2_secure_fullstack(
     grpc_end2end_test_fixture* f, grpc_channel_args* client_args) {
   grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
   grpc_channel_credentials* ssl_creds =
-      grpc_ssl_credentials_create(test_root_cert, NULL, NULL);
+      grpc_ssl_credentials_create(test_root_cert, nullptr, nullptr);
   grpc_call_credentials* oauth2_creds = grpc_md_only_test_credentials_create(
       &exec_ctx, "authorization", oauth2_md, true /* is_async */);
   grpc_channel_credentials* ssl_oauth2_creds =
-      grpc_composite_channel_credentials_create(ssl_creds, oauth2_creds, NULL);
+      grpc_composite_channel_credentials_create(ssl_creds, oauth2_creds, nullptr);
   grpc_arg ssl_name_override = {
       GRPC_ARG_STRING,
       const_cast<char*>(GRPC_SSL_TARGET_NAME_OVERRIDE_ARG),
@@ -165,7 +165,7 @@ static void chttp2_init_client_simple_ssl_with_oauth2_secure_fullstack(
 
 static int fail_server_auth_check(grpc_channel_args* server_args) {
   size_t i;
-  if (server_args == NULL) return 0;
+  if (server_args == nullptr) return 0;
   for (i = 0; i < server_args->num_args; i++) {
     if (strcmp(server_args->args[i].key, FAIL_AUTH_CHECK_SERVER_ARG_NAME) ==
         0) {
@@ -201,7 +201,7 @@ static void chttp2_init_server_simple_ssl_secure_fullstack(
   grpc_ssl_pem_key_cert_pair pem_key_cert_pair = {test_server1_key,
                                                   test_server1_cert};
   grpc_server_credentials* ssl_creds =
-      grpc_ssl_server_credentials_create(NULL, &pem_key_cert_pair, 1, 0, NULL);
+      grpc_ssl_server_credentials_create(nullptr, &pem_key_cert_pair, 1, 0, nullptr);
   grpc_server_credentials_set_auth_metadata_processor(
       ssl_creds, test_processor_create(fail_server_auth_check(server_args)));
   chttp2_init_server_secure_fullstack(f, server_args, ssl_creds);
diff --git a/test/core/end2end/fixtures/h2_proxy.cc b/test/core/end2end/fixtures/h2_proxy.cc
index 03ffa02e17..295654cb6a 100644
--- a/test/core/end2end/fixtures/h2_proxy.cc
+++ b/test/core/end2end/fixtures/h2_proxy.cc
@@ -42,14 +42,14 @@ typedef struct fullstack_fixture_data {
 
 static grpc_server* create_proxy_server(const char* port,
                                         grpc_channel_args* server_args) {
-  grpc_server* s = grpc_server_create(server_args, NULL);
+  grpc_server* s = grpc_server_create(server_args, nullptr);
   GPR_ASSERT(grpc_server_add_insecure_http2_port(s, port));
   return s;
 }
 
 static grpc_channel* create_proxy_client(const char* target,
                                          grpc_channel_args* client_args) {
-  return grpc_insecure_channel_create(target, client_args, NULL);
+  return grpc_insecure_channel_create(target, client_args, nullptr);
 }
 
 static const grpc_end2end_proxy_def proxy_def = {create_proxy_server,
@@ -65,8 +65,8 @@ static grpc_end2end_test_fixture chttp2_create_fixture_fullstack(
   ffd->proxy = grpc_end2end_proxy_create(&proxy_def, client_args, server_args);
 
   f.fixture_data = ffd;
-  f.cq = grpc_completion_queue_create_for_next(NULL);
-  f.shutdown_cq = grpc_completion_queue_create_for_pluck(NULL);
+  f.cq = grpc_completion_queue_create_for_next(nullptr);
+  f.shutdown_cq = grpc_completion_queue_create_for_pluck(nullptr);
 
   return f;
 }
@@ -76,7 +76,7 @@ void chttp2_init_client_fullstack(grpc_end2end_test_fixture* f,
   fullstack_fixture_data* ffd =
       static_cast<fullstack_fixture_data*>(f->fixture_data);
   f->client = grpc_insecure_channel_create(
-      grpc_end2end_proxy_get_client_target(ffd->proxy), client_args, NULL);
+      grpc_end2end_proxy_get_client_target(ffd->proxy), client_args, nullptr);
   GPR_ASSERT(f->client);
 }
 
@@ -87,8 +87,8 @@ void chttp2_init_server_fullstack(grpc_end2end_test_fixture* f,
   if (f->server) {
     grpc_server_destroy(f->server);
   }
-  f->server = grpc_server_create(server_args, NULL);
-  grpc_server_register_completion_queue(f->server, f->cq, NULL);
+  f->server = grpc_server_create(server_args, nullptr);
+  grpc_server_register_completion_queue(f->server, f->cq, nullptr);
   GPR_ASSERT(grpc_server_add_insecure_http2_port(
       f->server, grpc_end2end_proxy_get_server_port(ffd->proxy)));
   grpc_server_start(f->server);
diff --git a/test/core/end2end/fixtures/h2_sockpair+trace.cc b/test/core/end2end/fixtures/h2_sockpair+trace.cc
index c5dfe40391..fe4ab74843 100644
--- a/test/core/end2end/fixtures/h2_sockpair+trace.cc
+++ b/test/core/end2end/fixtures/h2_sockpair+trace.cc
@@ -53,7 +53,7 @@ static void server_setup_transport(void* ts, grpc_transport* transport) {
   grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
   grpc_endpoint_pair* sfd = static_cast<grpc_endpoint_pair*>(f->fixture_data);
   grpc_endpoint_add_to_pollset(&exec_ctx, sfd->server, grpc_cq_pollset(f->cq));
-  grpc_server_setup_transport(&exec_ctx, f->server, transport, NULL,
+  grpc_server_setup_transport(&exec_ctx, f->server, transport, nullptr,
                               grpc_server_get_channel_args(f->server));
   grpc_exec_ctx_finish(&exec_ctx);
 }
@@ -80,10 +80,10 @@ static grpc_end2end_test_fixture chttp2_create_fixture_socketpair(
   grpc_end2end_test_fixture f;
   memset(&f, 0, sizeof(f));
   f.fixture_data = sfd;
-  f.cq = grpc_completion_queue_create_for_next(NULL);
-  f.shutdown_cq = grpc_completion_queue_create_for_pluck(NULL);
+  f.cq = grpc_completion_queue_create_for_next(nullptr);
+  f.shutdown_cq = grpc_completion_queue_create_for_pluck(nullptr);
 
-  *sfd = grpc_iomgr_create_endpoint_pair("fixture", NULL);
+  *sfd = grpc_iomgr_create_endpoint_pair("fixture", nullptr);
 
   return f;
 }
@@ -100,7 +100,7 @@ static void chttp2_init_client_socketpair(grpc_end2end_test_fixture* f,
       grpc_create_chttp2_transport(&exec_ctx, client_args, sfd->client, 1);
   client_setup_transport(&exec_ctx, &cs, transport);
   GPR_ASSERT(f->client);
-  grpc_chttp2_transport_start_reading(&exec_ctx, transport, NULL);
+  grpc_chttp2_transport_start_reading(&exec_ctx, transport, nullptr);
   grpc_exec_ctx_finish(&exec_ctx);
 }
 
@@ -110,13 +110,13 @@ static void chttp2_init_server_socketpair(grpc_end2end_test_fixture* f,
   grpc_endpoint_pair* sfd = static_cast<grpc_endpoint_pair*>(f->fixture_data);
   grpc_transport* transport;
   GPR_ASSERT(!f->server);
-  f->server = grpc_server_create(server_args, NULL);
-  grpc_server_register_completion_queue(f->server, f->cq, NULL);
+  f->server = grpc_server_create(server_args, nullptr);
+  grpc_server_register_completion_queue(f->server, f->cq, nullptr);
   grpc_server_start(f->server);
   transport =
       grpc_create_chttp2_transport(&exec_ctx, server_args, sfd->server, 0);
   server_setup_transport(f, transport);
-  grpc_chttp2_transport_start_reading(&exec_ctx, transport, NULL);
+  grpc_chttp2_transport_start_reading(&exec_ctx, transport, nullptr);
   grpc_exec_ctx_finish(&exec_ctx);
 }
 
diff --git a/test/core/end2end/fixtures/h2_sockpair.cc b/test/core/end2end/fixtures/h2_sockpair.cc
index f07722e52d..59a3a6db31 100644
--- a/test/core/end2end/fixtures/h2_sockpair.cc
+++ b/test/core/end2end/fixtures/h2_sockpair.cc
@@ -47,7 +47,7 @@ static void server_setup_transport(void* ts, grpc_transport* transport) {
   grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
   grpc_endpoint_pair* sfd = static_cast<grpc_endpoint_pair*>(f->fixture_data);
   grpc_endpoint_add_to_pollset(&exec_ctx, sfd->server, grpc_cq_pollset(f->cq));
-  grpc_server_setup_transport(&exec_ctx, f->server, transport, NULL,
+  grpc_server_setup_transport(&exec_ctx, f->server, transport, nullptr,
                               grpc_server_get_channel_args(f->server));
   grpc_exec_ctx_finish(&exec_ctx);
 }
@@ -74,10 +74,10 @@ static grpc_end2end_test_fixture chttp2_create_fixture_socketpair(
   grpc_end2end_test_fixture f;
   memset(&f, 0, sizeof(f));
   f.fixture_data = sfd;
-  f.cq = grpc_completion_queue_create_for_next(NULL);
-  f.shutdown_cq = grpc_completion_queue_create_for_pluck(NULL);
+  f.cq = grpc_completion_queue_create_for_next(nullptr);
+  f.shutdown_cq = grpc_completion_queue_create_for_pluck(nullptr);
 
-  *sfd = grpc_iomgr_create_endpoint_pair("fixture", NULL);
+  *sfd = grpc_iomgr_create_endpoint_pair("fixture", nullptr);
 
   return f;
 }
@@ -94,7 +94,7 @@ static void chttp2_init_client_socketpair(grpc_end2end_test_fixture* f,
       grpc_create_chttp2_transport(&exec_ctx, client_args, sfd->client, 1);
   client_setup_transport(&exec_ctx, &cs, transport);
   GPR_ASSERT(f->client);
-  grpc_chttp2_transport_start_reading(&exec_ctx, transport, NULL);
+  grpc_chttp2_transport_start_reading(&exec_ctx, transport, nullptr);
   grpc_exec_ctx_finish(&exec_ctx);
 }
 
@@ -104,13 +104,13 @@ static void chttp2_init_server_socketpair(grpc_end2end_test_fixture* f,
   grpc_endpoint_pair* sfd = static_cast<grpc_endpoint_pair*>(f->fixture_data);
   grpc_transport* transport;
   GPR_ASSERT(!f->server);
-  f->server = grpc_server_create(server_args, NULL);
-  grpc_server_register_completion_queue(f->server, f->cq, NULL);
+  f->server = grpc_server_create(server_args, nullptr);
+  grpc_server_register_completion_queue(f->server, f->cq, nullptr);
   grpc_server_start(f->server);
   transport =
       grpc_create_chttp2_transport(&exec_ctx, server_args, sfd->server, 0);
   server_setup_transport(f, transport);
-  grpc_chttp2_transport_start_reading(&exec_ctx, transport, NULL);
+  grpc_chttp2_transport_start_reading(&exec_ctx, transport, nullptr);
   grpc_exec_ctx_finish(&exec_ctx);
 }
 
diff --git a/test/core/end2end/fixtures/h2_sockpair_1byte.cc b/test/core/end2end/fixtures/h2_sockpair_1byte.cc
index 7d00c69a18..d935efbbac 100644
--- a/test/core/end2end/fixtures/h2_sockpair_1byte.cc
+++ b/test/core/end2end/fixtures/h2_sockpair_1byte.cc
@@ -47,7 +47,7 @@ static void server_setup_transport(void* ts, grpc_transport* transport) {
   grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
   grpc_endpoint_pair* sfd = static_cast<grpc_endpoint_pair*>(f->fixture_data);
   grpc_endpoint_add_to_pollset(&exec_ctx, sfd->server, grpc_cq_pollset(f->cq));
-  grpc_server_setup_transport(&exec_ctx, f->server, transport, NULL,
+  grpc_server_setup_transport(&exec_ctx, f->server, transport, nullptr,
                               grpc_server_get_channel_args(f->server));
   grpc_exec_ctx_finish(&exec_ctx);
 }
@@ -74,8 +74,8 @@ static grpc_end2end_test_fixture chttp2_create_fixture_socketpair(
   grpc_end2end_test_fixture f;
   memset(&f, 0, sizeof(f));
   f.fixture_data = sfd;
-  f.cq = grpc_completion_queue_create_for_next(NULL);
-  f.shutdown_cq = grpc_completion_queue_create_for_pluck(NULL);
+  f.cq = grpc_completion_queue_create_for_next(nullptr);
+  f.shutdown_cq = grpc_completion_queue_create_for_pluck(nullptr);
 
   grpc_arg a[3];
   a[0].key = const_cast<char*>(GRPC_ARG_TCP_READ_CHUNK_SIZE);
@@ -105,7 +105,7 @@ static void chttp2_init_client_socketpair(grpc_end2end_test_fixture* f,
       grpc_create_chttp2_transport(&exec_ctx, client_args, sfd->client, 1);
   client_setup_transport(&exec_ctx, &cs, transport);
   GPR_ASSERT(f->client);
-  grpc_chttp2_transport_start_reading(&exec_ctx, transport, NULL);
+  grpc_chttp2_transport_start_reading(&exec_ctx, transport, nullptr);
   grpc_exec_ctx_finish(&exec_ctx);
 }
 
@@ -115,13 +115,13 @@ static void chttp2_init_server_socketpair(grpc_end2end_test_fixture* f,
   grpc_endpoint_pair* sfd = static_cast<grpc_endpoint_pair*>(f->fixture_data);
   grpc_transport* transport;
   GPR_ASSERT(!f->server);
-  f->server = grpc_server_create(server_args, NULL);
-  grpc_server_register_completion_queue(f->server, f->cq, NULL);
+  f->server = grpc_server_create(server_args, nullptr);
+  grpc_server_register_completion_queue(f->server, f->cq, nullptr);
   grpc_server_start(f->server);
   transport =
       grpc_create_chttp2_transport(&exec_ctx, server_args, sfd->server, 0);
   server_setup_transport(f, transport);
-  grpc_chttp2_transport_start_reading(&exec_ctx, transport, NULL);
+  grpc_chttp2_transport_start_reading(&exec_ctx, transport, nullptr);
   grpc_exec_ctx_finish(&exec_ctx);
 }
 
diff --git a/test/core/end2end/fixtures/h2_ssl.cc b/test/core/end2end/fixtures/h2_ssl.cc
index 70daefd333..047b5d7510 100644
--- a/test/core/end2end/fixtures/h2_ssl.cc
+++ b/test/core/end2end/fixtures/h2_ssl.cc
@@ -50,8 +50,8 @@ static grpc_end2end_test_fixture chttp2_create_fixture_secure_fullstack(
   gpr_join_host_port(&ffd->localaddr, "localhost", port);
 
   f.fixture_data = ffd;
-  f.cq = grpc_completion_queue_create_for_next(NULL);
-  f.shutdown_cq = grpc_completion_queue_create_for_pluck(NULL);
+  f.cq = grpc_completion_queue_create_for_next(nullptr);
+  f.shutdown_cq = grpc_completion_queue_create_for_pluck(nullptr);
 
   return f;
 }
@@ -60,8 +60,8 @@ static void process_auth_failure(void* state, grpc_auth_context* ctx,
                                  const grpc_metadata* md, size_t md_count,
                                  grpc_process_auth_metadata_done_cb cb,
                                  void* user_data) {
-  GPR_ASSERT(state == NULL);
-  cb(user_data, NULL, 0, NULL, 0, GRPC_STATUS_UNAUTHENTICATED, NULL);
+  GPR_ASSERT(state == nullptr);
+  cb(user_data, nullptr, 0, nullptr, 0, GRPC_STATUS_UNAUTHENTICATED, nullptr);
 }
 
 static void chttp2_init_client_secure_fullstack(
@@ -70,8 +70,8 @@ static void chttp2_init_client_secure_fullstack(
   fullstack_secure_fixture_data* ffd =
       static_cast<fullstack_secure_fixture_data*>(f->fixture_data);
   f->client =
-      grpc_secure_channel_create(creds, ffd->localaddr, client_args, NULL);
-  GPR_ASSERT(f->client != NULL);
+      grpc_secure_channel_create(creds, ffd->localaddr, client_args, nullptr);
+  GPR_ASSERT(f->client != nullptr);
   grpc_channel_credentials_release(creds);
 }
 
@@ -83,8 +83,8 @@ static void chttp2_init_server_secure_fullstack(
   if (f->server) {
     grpc_server_destroy(f->server);
   }
-  f->server = grpc_server_create(server_args, NULL);
-  grpc_server_register_completion_queue(f->server, f->cq, NULL);
+  f->server = grpc_server_create(server_args, nullptr);
+  grpc_server_register_completion_queue(f->server, f->cq, nullptr);
   GPR_ASSERT(grpc_server_add_secure_http2_port(f->server, ffd->localaddr,
                                                server_creds));
   grpc_server_credentials_release(server_creds);
@@ -101,7 +101,7 @@ void chttp2_tear_down_secure_fullstack(grpc_end2end_test_fixture* f) {
 static void chttp2_init_client_simple_ssl_secure_fullstack(
     grpc_end2end_test_fixture* f, grpc_channel_args* client_args) {
   grpc_channel_credentials* ssl_creds =
-      grpc_ssl_credentials_create(NULL, NULL, NULL);
+      grpc_ssl_credentials_create(nullptr, nullptr, nullptr);
   grpc_arg ssl_name_override = {
       GRPC_ARG_STRING,
       const_cast<char*>(GRPC_SSL_TARGET_NAME_OVERRIDE_ARG),
@@ -118,7 +118,7 @@ static void chttp2_init_client_simple_ssl_secure_fullstack(
 
 static int fail_server_auth_check(grpc_channel_args* server_args) {
   size_t i;
-  if (server_args == NULL) return 0;
+  if (server_args == nullptr) return 0;
   for (i = 0; i < server_args->num_args; i++) {
     if (strcmp(server_args->args[i].key, FAIL_AUTH_CHECK_SERVER_ARG_NAME) ==
         0) {
@@ -133,9 +133,9 @@ static void chttp2_init_server_simple_ssl_secure_fullstack(
   grpc_ssl_pem_key_cert_pair pem_cert_key_pair = {test_server1_key,
                                                   test_server1_cert};
   grpc_server_credentials* ssl_creds =
-      grpc_ssl_server_credentials_create(NULL, &pem_cert_key_pair, 1, 0, NULL);
+      grpc_ssl_server_credentials_create(nullptr, &pem_cert_key_pair, 1, 0, nullptr);
   if (fail_server_auth_check(server_args)) {
-    grpc_auth_metadata_processor processor = {process_auth_failure, NULL, NULL};
+    grpc_auth_metadata_processor processor = {process_auth_failure, nullptr, nullptr};
     grpc_server_credentials_set_auth_metadata_processor(ssl_creds, processor);
   }
   chttp2_init_server_secure_fullstack(f, server_args, ssl_creds);
@@ -166,8 +166,8 @@ int main(int argc, char** argv) {
 
   /* Set the SSL roots env var. */
   roots_file = gpr_tmpfile("chttp2_simple_ssl_fullstack_test", &roots_filename);
-  GPR_ASSERT(roots_filename != NULL);
-  GPR_ASSERT(roots_file != NULL);
+  GPR_ASSERT(roots_filename != nullptr);
+  GPR_ASSERT(roots_file != nullptr);
   GPR_ASSERT(fwrite(test_root_cert, 1, roots_size, roots_file) == roots_size);
   fclose(roots_file);
   gpr_setenv(GRPC_DEFAULT_SSL_ROOTS_FILE_PATH_ENV_VAR, roots_filename);
diff --git a/test/core/end2end/fixtures/h2_ssl_proxy.cc b/test/core/end2end/fixtures/h2_ssl_proxy.cc
index b3488a29e5..7191210261 100644
--- a/test/core/end2end/fixtures/h2_ssl_proxy.cc
+++ b/test/core/end2end/fixtures/h2_ssl_proxy.cc
@@ -41,11 +41,11 @@ typedef struct fullstack_secure_fixture_data {
 
 static grpc_server* create_proxy_server(const char* port,
                                         grpc_channel_args* server_args) {
-  grpc_server* s = grpc_server_create(server_args, NULL);
+  grpc_server* s = grpc_server_create(server_args, nullptr);
   grpc_ssl_pem_key_cert_pair pem_cert_key_pair = {test_server1_key,
                                                   test_server1_cert};
   grpc_server_credentials* ssl_creds =
-      grpc_ssl_server_credentials_create(NULL, &pem_cert_key_pair, 1, 0, NULL);
+      grpc_ssl_server_credentials_create(nullptr, &pem_cert_key_pair, 1, 0, nullptr);
   GPR_ASSERT(grpc_server_add_secure_http2_port(s, port, ssl_creds));
   grpc_server_credentials_release(ssl_creds);
   return s;
@@ -55,7 +55,7 @@ static grpc_channel* create_proxy_client(const char* target,
                                          grpc_channel_args* client_args) {
   grpc_channel* channel;
   grpc_channel_credentials* ssl_creds =
-      grpc_ssl_credentials_create(NULL, NULL, NULL);
+      grpc_ssl_credentials_create(nullptr, nullptr, nullptr);
   grpc_arg ssl_name_override = {
       GRPC_ARG_STRING,
       const_cast<char*>(GRPC_SSL_TARGET_NAME_OVERRIDE_ARG),
@@ -63,7 +63,7 @@ static grpc_channel* create_proxy_client(const char* target,
   grpc_channel_args* new_client_args =
       grpc_channel_args_copy_and_add(client_args, &ssl_name_override, 1);
   channel =
-      grpc_secure_channel_create(ssl_creds, target, new_client_args, NULL);
+      grpc_secure_channel_create(ssl_creds, target, new_client_args, nullptr);
   grpc_channel_credentials_release(ssl_creds);
   {
     grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
@@ -87,8 +87,8 @@ static grpc_end2end_test_fixture chttp2_create_fixture_secure_fullstack(
   ffd->proxy = grpc_end2end_proxy_create(&proxy_def, client_args, server_args);
 
   f.fixture_data = ffd;
-  f.cq = grpc_completion_queue_create_for_next(NULL);
-  f.shutdown_cq = grpc_completion_queue_create_for_pluck(NULL);
+  f.cq = grpc_completion_queue_create_for_next(nullptr);
+  f.shutdown_cq = grpc_completion_queue_create_for_pluck(nullptr);
 
   return f;
 }
@@ -97,8 +97,8 @@ static void process_auth_failure(void* state, grpc_auth_context* ctx,
                                  const grpc_metadata* md, size_t md_count,
                                  grpc_process_auth_metadata_done_cb cb,
                                  void* user_data) {
-  GPR_ASSERT(state == NULL);
-  cb(user_data, NULL, 0, NULL, 0, GRPC_STATUS_UNAUTHENTICATED, NULL);
+  GPR_ASSERT(state == nullptr);
+  cb(user_data, nullptr, 0, nullptr, 0, GRPC_STATUS_UNAUTHENTICATED, nullptr);
 }
 
 static void chttp2_init_client_secure_fullstack(
@@ -108,8 +108,8 @@ static void chttp2_init_client_secure_fullstack(
       static_cast<fullstack_secure_fixture_data*>(f->fixture_data);
   f->client = grpc_secure_channel_create(
       creds, grpc_end2end_proxy_get_client_target(ffd->proxy), client_args,
-      NULL);
-  GPR_ASSERT(f->client != NULL);
+      nullptr);
+  GPR_ASSERT(f->client != nullptr);
   grpc_channel_credentials_release(creds);
 }
 
@@ -121,8 +121,8 @@ static void chttp2_init_server_secure_fullstack(
   if (f->server) {
     grpc_server_destroy(f->server);
   }
-  f->server = grpc_server_create(server_args, NULL);
-  grpc_server_register_completion_queue(f->server, f->cq, NULL);
+  f->server = grpc_server_create(server_args, nullptr);
+  grpc_server_register_completion_queue(f->server, f->cq, nullptr);
   GPR_ASSERT(grpc_server_add_secure_http2_port(
       f->server, grpc_end2end_proxy_get_server_port(ffd->proxy), server_creds));
   grpc_server_credentials_release(server_creds);
@@ -139,7 +139,7 @@ void chttp2_tear_down_secure_fullstack(grpc_end2end_test_fixture* f) {
 static void chttp2_init_client_simple_ssl_secure_fullstack(
     grpc_end2end_test_fixture* f, grpc_channel_args* client_args) {
   grpc_channel_credentials* ssl_creds =
-      grpc_ssl_credentials_create(NULL, NULL, NULL);
+      grpc_ssl_credentials_create(nullptr, nullptr, nullptr);
   grpc_arg ssl_name_override = {
       GRPC_ARG_STRING,
       const_cast<char*>(GRPC_SSL_TARGET_NAME_OVERRIDE_ARG),
@@ -156,7 +156,7 @@ static void chttp2_init_client_simple_ssl_secure_fullstack(
 
 static int fail_server_auth_check(grpc_channel_args* server_args) {
   size_t i;
-  if (server_args == NULL) return 0;
+  if (server_args == nullptr) return 0;
   for (i = 0; i < server_args->num_args; i++) {
     if (strcmp(server_args->args[i].key, FAIL_AUTH_CHECK_SERVER_ARG_NAME) ==
         0) {
@@ -171,9 +171,9 @@ static void chttp2_init_server_simple_ssl_secure_fullstack(
   grpc_ssl_pem_key_cert_pair pem_cert_key_pair = {test_server1_key,
                                                   test_server1_cert};
   grpc_server_credentials* ssl_creds =
-      grpc_ssl_server_credentials_create(NULL, &pem_cert_key_pair, 1, 0, NULL);
+      grpc_ssl_server_credentials_create(nullptr, &pem_cert_key_pair, 1, 0, nullptr);
   if (fail_server_auth_check(server_args)) {
-    grpc_auth_metadata_processor processor = {process_auth_failure, NULL, NULL};
+    grpc_auth_metadata_processor processor = {process_auth_failure, nullptr, nullptr};
     grpc_server_credentials_set_auth_metadata_processor(ssl_creds, processor);
   }
   chttp2_init_server_secure_fullstack(f, server_args, ssl_creds);
@@ -205,8 +205,8 @@ int main(int argc, char** argv) {
 
   /* Set the SSL roots env var. */
   roots_file = gpr_tmpfile("chttp2_simple_ssl_fullstack_test", &roots_filename);
-  GPR_ASSERT(roots_filename != NULL);
-  GPR_ASSERT(roots_file != NULL);
+  GPR_ASSERT(roots_filename != nullptr);
+  GPR_ASSERT(roots_file != nullptr);
   GPR_ASSERT(fwrite(test_root_cert, 1, roots_size, roots_file) == roots_size);
   fclose(roots_file);
   gpr_setenv(GRPC_DEFAULT_SSL_ROOTS_FILE_PATH_ENV_VAR, roots_filename);
diff --git a/test/core/end2end/fixtures/h2_uds.cc b/test/core/end2end/fixtures/h2_uds.cc
index ba433df57b..553244f800 100644
--- a/test/core/end2end/fixtures/h2_uds.cc
+++ b/test/core/end2end/fixtures/h2_uds.cc
@@ -56,8 +56,8 @@ static grpc_end2end_test_fixture chttp2_create_fixture_fullstack(
                unique++);
 
   f.fixture_data = ffd;
-  f.cq = grpc_completion_queue_create_for_next(NULL);
-  f.shutdown_cq = grpc_completion_queue_create_for_pluck(NULL);
+  f.cq = grpc_completion_queue_create_for_next(nullptr);
+  f.shutdown_cq = grpc_completion_queue_create_for_pluck(nullptr);
 
   return f;
 }
@@ -66,7 +66,7 @@ void chttp2_init_client_fullstack(grpc_end2end_test_fixture* f,
                                   grpc_channel_args* client_args) {
   fullstack_fixture_data* ffd =
       static_cast<fullstack_fixture_data*>(f->fixture_data);
-  f->client = grpc_insecure_channel_create(ffd->localaddr, client_args, NULL);
+  f->client = grpc_insecure_channel_create(ffd->localaddr, client_args, nullptr);
 }
 
 void chttp2_init_server_fullstack(grpc_end2end_test_fixture* f,
@@ -76,8 +76,8 @@ void chttp2_init_server_fullstack(grpc_end2end_test_fixture* f,
   if (f->server) {
     grpc_server_destroy(f->server);
   }
-  f->server = grpc_server_create(server_args, NULL);
-  grpc_server_register_completion_queue(f->server, f->cq, NULL);
+  f->server = grpc_server_create(server_args, nullptr);
+  grpc_server_register_completion_queue(f->server, f->cq, nullptr);
   GPR_ASSERT(grpc_server_add_insecure_http2_port(f->server, ffd->localaddr));
   grpc_server_start(f->server);
 }
diff --git a/test/core/end2end/fixtures/http_proxy_fixture.cc b/test/core/end2end/fixtures/http_proxy_fixture.cc
index d29401fdc3..ab4197e95c 100644
--- a/test/core/end2end/fixtures/http_proxy_fixture.cc
+++ b/test/core/end2end/fixtures/http_proxy_fixture.cc
@@ -108,7 +108,7 @@ static void proxy_connection_unref(grpc_exec_ctx* exec_ctx,
     gpr_log(GPR_DEBUG, "endpoints: %p %p", conn->client_endpoint,
             conn->server_endpoint);
     grpc_endpoint_destroy(exec_ctx, conn->client_endpoint);
-    if (conn->server_endpoint != NULL) {
+    if (conn->server_endpoint != nullptr) {
       grpc_endpoint_destroy(exec_ctx, conn->server_endpoint);
     }
     grpc_pollset_set_destroy(exec_ctx, conn->pollset_set);
@@ -137,7 +137,7 @@ static void proxy_connection_failed(grpc_exec_ctx* exec_ctx,
 
   grpc_endpoint_shutdown(exec_ctx, conn->client_endpoint,
                          GRPC_ERROR_REF(error));
-  if (conn->server_endpoint != NULL) {
+  if (conn->server_endpoint != nullptr) {
     grpc_endpoint_shutdown(exec_ctx, conn->server_endpoint,
                            GRPC_ERROR_REF(error));
   }
@@ -315,8 +315,8 @@ static void on_server_connect_done(grpc_exec_ctx* exec_ctx, void* arg,
 static bool proxy_auth_header_matches(grpc_exec_ctx* exec_ctx,
                                       char* proxy_auth_header_val,
                                       char* expected_cred) {
-  GPR_ASSERT(proxy_auth_header_val != NULL);
-  GPR_ASSERT(expected_cred != NULL);
+  GPR_ASSERT(proxy_auth_header_val != nullptr);
+  GPR_ASSERT(expected_cred != nullptr);
   if (strncmp(proxy_auth_header_val, "Basic ", 6) != 0) {
     return false;
   }
@@ -349,7 +349,7 @@ static void on_read_request_done(grpc_exec_ctx* exec_ctx, void* arg,
   for (size_t i = 0; i < conn->client_read_buffer.count; ++i) {
     if (GRPC_SLICE_LENGTH(conn->client_read_buffer.slices[i]) > 0) {
       error = grpc_http_parser_parse(&conn->http_parser,
-                                     conn->client_read_buffer.slices[i], NULL);
+                                     conn->client_read_buffer.slices[i], nullptr);
       if (error != GRPC_ERROR_NONE) {
         proxy_connection_failed(exec_ctx, conn, true /* is_client */,
                                 "HTTP proxy request parse", error);
@@ -380,7 +380,7 @@ static void on_read_request_done(grpc_exec_ctx* exec_ctx, void* arg,
   // If proxy auth is being used, check if the header is present and as expected
   const grpc_arg* proxy_auth_arg = grpc_channel_args_find(
       conn->proxy->channel_args, GRPC_ARG_HTTP_PROXY_AUTH_CREDS);
-  if (proxy_auth_arg != NULL && proxy_auth_arg->type == GRPC_ARG_STRING) {
+  if (proxy_auth_arg != nullptr && proxy_auth_arg->type == GRPC_ARG_STRING) {
     bool client_authenticated = false;
     for (size_t i = 0; i < conn->http_request.hdr_count; i++) {
       if (strcmp(conn->http_request.hdrs[i].key, "Proxy-Authorization") == 0) {
@@ -400,7 +400,7 @@ static void on_read_request_done(grpc_exec_ctx* exec_ctx, void* arg,
     }
   }
   // Resolve address.
-  grpc_resolved_addresses* resolved_addresses = NULL;
+  grpc_resolved_addresses* resolved_addresses = nullptr;
   error = grpc_blocking_resolve_address(conn->http_request.path, "80",
                                         &resolved_addresses);
   if (error != GRPC_ERROR_NONE) {
@@ -415,7 +415,7 @@ static void on_read_request_done(grpc_exec_ctx* exec_ctx, void* arg,
   const grpc_millis deadline =
       grpc_exec_ctx_now(exec_ctx) + 10 * GPR_MS_PER_SEC;
   grpc_tcp_client_connect(exec_ctx, &conn->on_server_connect_done,
-                          &conn->server_endpoint, conn->pollset_set, NULL,
+                          &conn->server_endpoint, conn->pollset_set, nullptr,
                           &resolved_addresses->addrs[0], deadline);
   grpc_resolved_addresses_destroy(resolved_addresses);
 }
@@ -469,7 +469,7 @@ static void thread_main(void* arg) {
   grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
   do {
     gpr_ref(&proxy->users);
-    grpc_pollset_worker* worker = NULL;
+    grpc_pollset_worker* worker = nullptr;
     gpr_mu_lock(proxy->mu);
     GRPC_LOG_IF_ERROR(
         "grpc_pollset_work",
@@ -496,7 +496,7 @@ grpc_end2end_http_proxy* grpc_end2end_http_proxy_create(
   // Create TCP server.
   proxy->channel_args = grpc_channel_args_copy(args);
   grpc_error* error = grpc_tcp_server_create(
-      &exec_ctx, NULL, proxy->channel_args, &proxy->server);
+      &exec_ctx, nullptr, proxy->channel_args, &proxy->server);
   GPR_ASSERT(error == GRPC_ERROR_NONE);
   // Bind to port.
   grpc_resolved_address resolved_addr;
diff --git a/test/core/end2end/fixtures/inproc.cc b/test/core/end2end/fixtures/inproc.cc
index 5107ed2018..b748fbf09a 100644
--- a/test/core/end2end/fixtures/inproc.cc
+++ b/test/core/end2end/fixtures/inproc.cc
@@ -47,15 +47,15 @@ static grpc_end2end_test_fixture inproc_create_fixture(
   memset(&f, 0, sizeof(f));
 
   f.fixture_data = ffd;
-  f.cq = grpc_completion_queue_create_for_next(NULL);
-  f.shutdown_cq = grpc_completion_queue_create_for_pluck(NULL);
+  f.cq = grpc_completion_queue_create_for_next(nullptr);
+  f.shutdown_cq = grpc_completion_queue_create_for_pluck(nullptr);
 
   return f;
 }
 
 void inproc_init_client(grpc_end2end_test_fixture* f,
                         grpc_channel_args* client_args) {
-  f->client = grpc_inproc_channel_create(f->server, client_args, NULL);
+  f->client = grpc_inproc_channel_create(f->server, client_args, nullptr);
   GPR_ASSERT(f->client);
 }
 
@@ -64,8 +64,8 @@ void inproc_init_server(grpc_end2end_test_fixture* f,
   if (f->server) {
     grpc_server_destroy(f->server);
   }
-  f->server = grpc_server_create(server_args, NULL);
-  grpc_server_register_completion_queue(f->server, f->cq, NULL);
+  f->server = grpc_server_create(server_args, nullptr);
+  grpc_server_register_completion_queue(f->server, f->cq, nullptr);
   grpc_server_start(f->server);
 }
 
diff --git a/test/core/end2end/fixtures/proxy.cc b/test/core/end2end/fixtures/proxy.cc
index 01c9e13538..3d3eed495c 100644
--- a/test/core/end2end/fixtures/proxy.cc
+++ b/test/core/end2end/fixtures/proxy.cc
@@ -89,11 +89,11 @@ grpc_end2end_proxy* grpc_end2end_proxy_create(const grpc_end2end_proxy_def* def,
   gpr_log(GPR_DEBUG, "PROXY ADDR:%s BACKEND:%s", proxy->proxy_port,
           proxy->server_port);
 
-  proxy->cq = grpc_completion_queue_create_for_next(NULL);
+  proxy->cq = grpc_completion_queue_create_for_next(nullptr);
   proxy->server = def->create_server(proxy->proxy_port, server_args);
   proxy->client = def->create_client(proxy->server_port, client_args);
 
-  grpc_server_register_completion_queue(proxy->server, proxy->cq, NULL);
+  grpc_server_register_completion_queue(proxy->server, proxy->cq, nullptr);
   grpc_server_start(proxy->server);
 
   grpc_call_details_init(&proxy->new_call_details);
@@ -159,12 +159,12 @@ static void on_p2s_recv_initial_metadata(void* arg, int success) {
   if (!pc->proxy->shutdown) {
     op.op = GRPC_OP_SEND_INITIAL_METADATA;
     op.flags = 0;
-    op.reserved = NULL;
+    op.reserved = nullptr;
     op.data.send_initial_metadata.count = pc->p2s_initial_metadata.count;
     op.data.send_initial_metadata.metadata = pc->p2s_initial_metadata.metadata;
     refpc(pc, "on_c2p_sent_initial_metadata");
     err = grpc_call_start_batch(
-        pc->c2p, &op, 1, new_closure(on_c2p_sent_initial_metadata, pc), NULL);
+        pc->c2p, &op, 1, new_closure(on_c2p_sent_initial_metadata, pc), nullptr);
     GPR_ASSERT(err == GRPC_CALL_OK);
   }
 
@@ -187,11 +187,11 @@ static void on_p2s_sent_message(void* arg, int success) {
   if (!pc->proxy->shutdown && success) {
     op.op = GRPC_OP_RECV_MESSAGE;
     op.flags = 0;
-    op.reserved = NULL;
+    op.reserved = nullptr;
     op.data.recv_message.recv_message = &pc->c2p_msg;
     refpc(pc, "on_c2p_recv_msg");
     err = grpc_call_start_batch(pc->c2p, &op, 1,
-                                new_closure(on_c2p_recv_msg, pc), NULL);
+                                new_closure(on_c2p_recv_msg, pc), nullptr);
     GPR_ASSERT(err == GRPC_CALL_OK);
   }
 
@@ -209,26 +209,26 @@ static void on_c2p_recv_msg(void* arg, int success) {
   grpc_call_error err;
 
   if (!pc->proxy->shutdown && success) {
-    if (pc->c2p_msg != NULL) {
+    if (pc->c2p_msg != nullptr) {
       op.op = GRPC_OP_SEND_MESSAGE;
       op.flags = 0;
-      op.reserved = NULL;
+      op.reserved = nullptr;
       op.data.send_message.send_message = pc->c2p_msg;
       refpc(pc, "on_p2s_sent_message");
       err = grpc_call_start_batch(pc->p2s, &op, 1,
-                                  new_closure(on_p2s_sent_message, pc), NULL);
+                                  new_closure(on_p2s_sent_message, pc), nullptr);
       GPR_ASSERT(err == GRPC_CALL_OK);
     } else {
       op.op = GRPC_OP_SEND_CLOSE_FROM_CLIENT;
       op.flags = 0;
-      op.reserved = NULL;
+      op.reserved = nullptr;
       refpc(pc, "on_p2s_sent_close");
       err = grpc_call_start_batch(pc->p2s, &op, 1,
-                                  new_closure(on_p2s_sent_close, pc), NULL);
+                                  new_closure(on_p2s_sent_close, pc), nullptr);
       GPR_ASSERT(err == GRPC_CALL_OK);
     }
   } else {
-    if (pc->c2p_msg != NULL) {
+    if (pc->c2p_msg != nullptr) {
       grpc_byte_buffer_destroy(pc->c2p_msg);
     }
   }
@@ -247,11 +247,11 @@ static void on_c2p_sent_message(void* arg, int success) {
   if (!pc->proxy->shutdown && success) {
     op.op = GRPC_OP_RECV_MESSAGE;
     op.flags = 0;
-    op.reserved = NULL;
+    op.reserved = nullptr;
     op.data.recv_message.recv_message = &pc->p2s_msg;
     refpc(pc, "on_p2s_recv_msg");
     err = grpc_call_start_batch(pc->p2s, &op, 1,
-                                new_closure(on_p2s_recv_msg, pc), NULL);
+                                new_closure(on_p2s_recv_msg, pc), nullptr);
     GPR_ASSERT(err == GRPC_CALL_OK);
   }
 
@@ -266,11 +266,11 @@ static void on_p2s_recv_msg(void* arg, int success) {
   if (!pc->proxy->shutdown && success && pc->p2s_msg) {
     op.op = GRPC_OP_SEND_MESSAGE;
     op.flags = 0;
-    op.reserved = NULL;
+    op.reserved = nullptr;
     op.data.send_message.send_message = pc->p2s_msg;
     refpc(pc, "on_c2p_sent_message");
     err = grpc_call_start_batch(pc->c2p, &op, 1,
-                                new_closure(on_c2p_sent_message, pc), NULL);
+                                new_closure(on_c2p_sent_message, pc), nullptr);
     GPR_ASSERT(err == GRPC_CALL_OK);
   } else {
     grpc_byte_buffer_destroy(pc->p2s_msg);
@@ -292,7 +292,7 @@ static void on_p2s_status(void* arg, int success) {
     GPR_ASSERT(success);
     op.op = GRPC_OP_SEND_STATUS_FROM_SERVER;
     op.flags = 0;
-    op.reserved = NULL;
+    op.reserved = nullptr;
     op.data.send_status_from_server.trailing_metadata_count =
         pc->p2s_trailing_metadata.count;
     op.data.send_status_from_server.trailing_metadata =
@@ -301,7 +301,7 @@ static void on_p2s_status(void* arg, int success) {
     op.data.send_status_from_server.status_details = &pc->p2s_status_details;
     refpc(pc, "on_c2p_sent_status");
     err = grpc_call_start_batch(pc->c2p, &op, 1,
-                                new_closure(on_c2p_sent_status, pc), NULL);
+                                new_closure(on_c2p_sent_status, pc), nullptr);
     GPR_ASSERT(err == GRPC_CALL_OK);
   }
 
@@ -329,10 +329,10 @@ static void on_new_call(void* arg, int success) {
     pc->p2s = grpc_channel_create_call(
         proxy->client, pc->c2p, GRPC_PROPAGATE_DEFAULTS, proxy->cq,
         proxy->new_call_details.method, &proxy->new_call_details.host,
-        proxy->new_call_details.deadline, NULL);
+        proxy->new_call_details.deadline, nullptr);
     gpr_ref_init(&pc->refs, 1);
 
-    op.reserved = NULL;
+    op.reserved = nullptr;
 
     op.op = GRPC_OP_RECV_INITIAL_METADATA;
     op.flags = 0;
@@ -340,7 +340,7 @@ static void on_new_call(void* arg, int success) {
         &pc->p2s_initial_metadata;
     refpc(pc, "on_p2s_recv_initial_metadata");
     err = grpc_call_start_batch(
-        pc->p2s, &op, 1, new_closure(on_p2s_recv_initial_metadata, pc), NULL);
+        pc->p2s, &op, 1, new_closure(on_p2s_recv_initial_metadata, pc), nullptr);
     GPR_ASSERT(err == GRPC_CALL_OK);
 
     op.op = GRPC_OP_SEND_INITIAL_METADATA;
@@ -349,7 +349,7 @@ static void on_new_call(void* arg, int success) {
     op.data.send_initial_metadata.metadata = pc->c2p_initial_metadata.metadata;
     refpc(pc, "on_p2s_sent_initial_metadata");
     err = grpc_call_start_batch(
-        pc->p2s, &op, 1, new_closure(on_p2s_sent_initial_metadata, pc), NULL);
+        pc->p2s, &op, 1, new_closure(on_p2s_sent_initial_metadata, pc), nullptr);
     GPR_ASSERT(err == GRPC_CALL_OK);
 
     op.op = GRPC_OP_RECV_MESSAGE;
@@ -357,7 +357,7 @@ static void on_new_call(void* arg, int success) {
     op.data.recv_message.recv_message = &pc->c2p_msg;
     refpc(pc, "on_c2p_recv_msg");
     err = grpc_call_start_batch(pc->c2p, &op, 1,
-                                new_closure(on_c2p_recv_msg, pc), NULL);
+                                new_closure(on_c2p_recv_msg, pc), nullptr);
     GPR_ASSERT(err == GRPC_CALL_OK);
 
     op.op = GRPC_OP_RECV_MESSAGE;
@@ -365,7 +365,7 @@ static void on_new_call(void* arg, int success) {
     op.data.recv_message.recv_message = &pc->p2s_msg;
     refpc(pc, "on_p2s_recv_msg");
     err = grpc_call_start_batch(pc->p2s, &op, 1,
-                                new_closure(on_p2s_recv_msg, pc), NULL);
+                                new_closure(on_p2s_recv_msg, pc), nullptr);
     GPR_ASSERT(err == GRPC_CALL_OK);
 
     op.op = GRPC_OP_RECV_STATUS_ON_CLIENT;
@@ -376,7 +376,7 @@ static void on_new_call(void* arg, int success) {
     op.data.recv_status_on_client.status_details = &pc->p2s_status_details;
     refpc(pc, "on_p2s_status");
     err = grpc_call_start_batch(pc->p2s, &op, 1, new_closure(on_p2s_status, pc),
-                                NULL);
+                                nullptr);
     GPR_ASSERT(err == GRPC_CALL_OK);
 
     op.op = GRPC_OP_RECV_CLOSE_ON_SERVER;
@@ -384,7 +384,7 @@ static void on_new_call(void* arg, int success) {
     op.data.recv_close_on_server.cancelled = &pc->c2p_server_cancelled;
     refpc(pc, "on_c2p_closed");
     err = grpc_call_start_batch(pc->c2p, &op, 1, new_closure(on_c2p_closed, pc),
-                                NULL);
+                                nullptr);
     GPR_ASSERT(err == GRPC_CALL_OK);
 
     request_call(proxy);
@@ -394,12 +394,12 @@ static void on_new_call(void* arg, int success) {
 
     unrefpc(pc, "init");
   } else {
-    GPR_ASSERT(proxy->new_call == NULL);
+    GPR_ASSERT(proxy->new_call == nullptr);
   }
 }
 
 static void request_call(grpc_end2end_proxy* proxy) {
-  proxy->new_call = NULL;
+  proxy->new_call = nullptr;
   GPR_ASSERT(GRPC_CALL_OK == grpc_server_request_call(
                                  proxy->server, &proxy->new_call,
                                  &proxy->new_call_details,
@@ -412,7 +412,7 @@ static void thread_main(void* arg) {
   closure* cl;
   for (;;) {
     grpc_event ev = grpc_completion_queue_next(
-        proxy->cq, gpr_inf_future(GPR_CLOCK_MONOTONIC), NULL);
+        proxy->cq, gpr_inf_future(GPR_CLOCK_MONOTONIC), nullptr);
     switch (ev.type) {
       case GRPC_QUEUE_TIMEOUT:
         gpr_log(GPR_ERROR, "Should never reach here");
diff --git a/test/core/end2end/fuzzers/api_fuzzer.cc b/test/core/end2end/fuzzers/api_fuzzer.cc
index 69a5670d22..4ee063fc84 100644
--- a/test/core/end2end/fuzzers/api_fuzzer.cc
+++ b/test/core/end2end/fuzzers/api_fuzzer.cc
@@ -84,7 +84,7 @@ static uint8_t next_byte(input_stream* inp) {
 static void end(input_stream* inp) { inp->cur = inp->end; }
 
 static char* read_string(input_stream* inp, bool* special) {
-  char* str = NULL;
+  char* str = nullptr;
   size_t cap = 0;
   size_t sz = 0;
   char c;
@@ -96,7 +96,7 @@ static char* read_string(input_stream* inp, bool* special) {
     c = (char)next_byte(inp);
     str[sz++] = c;
   } while (c != 0 && c != 1);
-  if (special != NULL) {
+  if (special != nullptr) {
     *special = (c == 1);
   }
   if (c == 1) {
@@ -109,10 +109,10 @@ static void read_buffer(input_stream* inp, char** buffer, size_t* length,
                         bool* special) {
   *length = next_byte(inp);
   if (*length == 255) {
-    if (special != NULL) *special = true;
+    if (special != nullptr) *special = true;
     *length = next_byte(inp);
   } else {
-    if (special != NULL) *special = false;
+    if (special != nullptr) *special = false;
   }
   *buffer = static_cast<char*>(gpr_malloc(*length));
   for (size_t i = 0; i < *length; i++) {
@@ -201,12 +201,12 @@ static grpc_channel_args* read_args(input_stream* inp) {
     switch (next_byte(inp)) {
       case 1:
         args[i].type = GRPC_ARG_STRING;
-        args[i].key = read_string(inp, NULL);
-        args[i].value.string = read_string(inp, NULL);
+        args[i].key = read_string(inp, nullptr);
+        args[i].value.string = read_string(inp, nullptr);
         break;
       case 2:
         args[i].type = GRPC_ARG_INTEGER;
-        args[i].key = read_string(inp, NULL);
+        args[i].key = read_string(inp, nullptr);
         args[i].value.integer = read_int(inp);
         break;
       case 3:
@@ -248,11 +248,11 @@ static const char* read_cred_artifact(cred_artifact_ctx* ctx, input_stream* inp,
                                       const char** builtins,
                                       size_t num_builtins) {
   uint8_t b = next_byte(inp);
-  if (b == 0) return NULL;
-  if (b == 1) return ctx->release[ctx->num_release++] = read_string(inp, NULL);
+  if (b == 0) return nullptr;
+  if (b == 1) return ctx->release[ctx->num_release++] = read_string(inp, nullptr);
   if (b >= num_builtins + 1) {
     end(inp);
-    return NULL;
+    return nullptr;
   }
   return builtins[b - 1];
 }
@@ -272,8 +272,8 @@ static grpc_channel_credentials* read_ssl_channel_creds(input_stream* inp) {
                                          GPR_ARRAY_SIZE(builtin_cert_chains));
   grpc_ssl_pem_key_cert_pair key_cert_pair = {private_key, certs};
   grpc_channel_credentials* creds = grpc_ssl_credentials_create(
-      root_certs, private_key != NULL && certs != NULL ? &key_cert_pair : NULL,
-      NULL);
+      root_certs, private_key != nullptr && certs != nullptr ? &key_cert_pair : nullptr,
+      nullptr);
   cred_artifact_ctx_finish(&ctx);
   return creds;
 }
@@ -282,45 +282,45 @@ static grpc_call_credentials* read_call_creds(input_stream* inp) {
   switch (next_byte(inp)) {
     default:
       end(inp);
-      return NULL;
+      return nullptr;
     case 0:
-      return NULL;
+      return nullptr;
     case 1: {
       grpc_call_credentials* c1 = read_call_creds(inp);
       grpc_call_credentials* c2 = read_call_creds(inp);
-      if (c1 != NULL && c2 != NULL) {
+      if (c1 != nullptr && c2 != nullptr) {
         grpc_call_credentials* out =
-            grpc_composite_call_credentials_create(c1, c2, NULL);
+            grpc_composite_call_credentials_create(c1, c2, nullptr);
         grpc_call_credentials_release(c1);
         grpc_call_credentials_release(c2);
         return out;
-      } else if (c1 != NULL) {
+      } else if (c1 != nullptr) {
         return c1;
-      } else if (c2 != NULL) {
+      } else if (c2 != nullptr) {
         return c2;
       } else {
-        return NULL;
+        return nullptr;
       }
-      GPR_UNREACHABLE_CODE(return NULL);
+      GPR_UNREACHABLE_CODE(return nullptr);
     }
     case 2: {
       cred_artifact_ctx ctx = CRED_ARTIFACT_CTX_INIT;
-      const char* access_token = read_cred_artifact(&ctx, inp, NULL, 0);
+      const char* access_token = read_cred_artifact(&ctx, inp, nullptr, 0);
       grpc_call_credentials* out =
-          access_token == NULL
-              ? NULL
-              : grpc_access_token_credentials_create(access_token, NULL);
+          access_token == nullptr
+              ? nullptr
+              : grpc_access_token_credentials_create(access_token, nullptr);
       cred_artifact_ctx_finish(&ctx);
       return out;
     }
     case 3: {
       cred_artifact_ctx ctx = CRED_ARTIFACT_CTX_INIT;
-      const char* auth_token = read_cred_artifact(&ctx, inp, NULL, 0);
-      const char* auth_selector = read_cred_artifact(&ctx, inp, NULL, 0);
-      grpc_call_credentials* out = auth_token == NULL || auth_selector == NULL
-                                       ? NULL
+      const char* auth_token = read_cred_artifact(&ctx, inp, nullptr, 0);
+      const char* auth_selector = read_cred_artifact(&ctx, inp, nullptr, 0);
+      grpc_call_credentials* out = auth_token == nullptr || auth_selector == nullptr
+                                       ? nullptr
                                        : grpc_google_iam_credentials_create(
-                                             auth_token, auth_selector, NULL);
+                                             auth_token, auth_selector, nullptr);
       cred_artifact_ctx_finish(&ctx);
       return out;
     }
@@ -336,9 +336,9 @@ static grpc_channel_credentials* read_channel_creds(input_stream* inp) {
     case 1: {
       grpc_channel_credentials* c1 = read_channel_creds(inp);
       grpc_call_credentials* c2 = read_call_creds(inp);
-      if (c1 != NULL && c2 != NULL) {
+      if (c1 != nullptr && c2 != nullptr) {
         grpc_channel_credentials* out =
-            grpc_composite_channel_credentials_create(c1, c2, NULL);
+            grpc_composite_channel_credentials_create(c1, c2, nullptr);
         grpc_channel_credentials_release(c1);
         grpc_call_credentials_release(c2);
         return out;
@@ -346,17 +346,17 @@ static grpc_channel_credentials* read_channel_creds(input_stream* inp) {
         return c1;
       } else if (c2) {
         grpc_call_credentials_release(c2);
-        return NULL;
+        return nullptr;
       } else {
-        return NULL;
+        return nullptr;
       }
-      GPR_UNREACHABLE_CODE(return NULL);
+      GPR_UNREACHABLE_CODE(return nullptr);
     }
     case 2:
-      return NULL;
+      return nullptr;
     default:
       end(inp);
-      return NULL;
+      return nullptr;
   }
 }
 
@@ -378,7 +378,7 @@ static void finish_resolve(grpc_exec_ctx* exec_ctx, void* arg,
   addr_req* r = static_cast<addr_req*>(arg);
 
   if (error == GRPC_ERROR_NONE && 0 == strcmp(r->addr, "server")) {
-    if (r->addrs != NULL) {
+    if (r->addrs != nullptr) {
       grpc_resolved_addresses* addrs =
           static_cast<grpc_resolved_addresses*>(gpr_malloc(sizeof(*addrs)));
       addrs->naddrs = 1;
@@ -386,9 +386,9 @@ static void finish_resolve(grpc_exec_ctx* exec_ctx, void* arg,
           gpr_malloc(sizeof(*addrs->addrs)));
       addrs->addrs[0].len = 0;
       *r->addrs = addrs;
-    } else if (r->lb_addrs != NULL) {
-      grpc_lb_addresses* lb_addrs = grpc_lb_addresses_create(1, NULL);
-      grpc_lb_addresses_set_address(lb_addrs, 0, NULL, 0, false, NULL, NULL);
+    } else if (r->lb_addrs != nullptr) {
+      grpc_lb_addresses* lb_addrs = grpc_lb_addresses_create(1, nullptr);
+      grpc_lb_addresses_set_address(lb_addrs, 0, nullptr, 0, false, nullptr, nullptr);
       *r->lb_addrs = lb_addrs;
     }
     GRPC_CLOSURE_SCHED(exec_ctx, r->on_done, GRPC_ERROR_NONE);
@@ -411,7 +411,7 @@ void my_resolve_address(grpc_exec_ctx* exec_ctx, const char* addr,
   r->addr = gpr_strdup(addr);
   r->on_done = on_done;
   r->addrs = addresses;
-  r->lb_addrs = NULL;
+  r->lb_addrs = nullptr;
   grpc_timer_init(
       exec_ctx, &r->timer, GPR_MS_PER_SEC + grpc_exec_ctx_now(exec_ctx),
       GRPC_CLOSURE_CREATE(finish_resolve, r, grpc_schedule_on_exec_ctx));
@@ -425,12 +425,12 @@ grpc_ares_request* my_dns_lookup_ares(
   addr_req* r = static_cast<addr_req*>(gpr_malloc(sizeof(*r)));
   r->addr = gpr_strdup(addr);
   r->on_done = on_done;
-  r->addrs = NULL;
+  r->addrs = nullptr;
   r->lb_addrs = lb_addrs;
   grpc_timer_init(
       exec_ctx, &r->timer, GPR_MS_PER_SEC + grpc_exec_ctx_now(exec_ctx),
       GRPC_CLOSURE_CREATE(finish_resolve, r, grpc_schedule_on_exec_ctx));
-  return NULL;
+  return nullptr;
 }
 
 ////////////////////////////////////////////////////////////////////////////////
@@ -455,18 +455,18 @@ typedef struct {
 static void do_connect(grpc_exec_ctx* exec_ctx, void* arg, grpc_error* error) {
   future_connect* fc = static_cast<future_connect*>(arg);
   if (error != GRPC_ERROR_NONE) {
-    *fc->ep = NULL;
+    *fc->ep = nullptr;
     GRPC_CLOSURE_SCHED(exec_ctx, fc->closure, GRPC_ERROR_REF(error));
-  } else if (g_server != NULL) {
+  } else if (g_server != nullptr) {
     grpc_endpoint* client;
     grpc_endpoint* server;
-    grpc_passthru_endpoint_create(&client, &server, g_resource_quota, NULL);
+    grpc_passthru_endpoint_create(&client, &server, g_resource_quota, nullptr);
     *fc->ep = client;
 
     grpc_transport* transport =
-        grpc_create_chttp2_transport(exec_ctx, NULL, server, 0);
-    grpc_server_setup_transport(exec_ctx, g_server, transport, NULL, NULL);
-    grpc_chttp2_transport_start_reading(exec_ctx, transport, NULL);
+        grpc_create_chttp2_transport(exec_ctx, nullptr, server, 0);
+    grpc_server_setup_transport(exec_ctx, g_server, transport, nullptr, nullptr);
+    grpc_chttp2_transport_start_reading(exec_ctx, transport, nullptr);
 
     GRPC_CLOSURE_SCHED(exec_ctx, fc->closure, GRPC_ERROR_NONE);
   } else {
@@ -478,7 +478,7 @@ static void do_connect(grpc_exec_ctx* exec_ctx, void* arg, grpc_error* error) {
 static void sched_connect(grpc_exec_ctx* exec_ctx, grpc_closure* closure,
                           grpc_endpoint** ep, gpr_timespec deadline) {
   if (gpr_time_cmp(deadline, gpr_now(deadline.clock_type)) < 0) {
-    *ep = NULL;
+    *ep = nullptr;
     GRPC_CLOSURE_SCHED(
         exec_ctx, closure,
         GRPC_ERROR_CREATE_FROM_STATIC_STRING("Connect deadline exceeded"));
@@ -551,7 +551,7 @@ static void validate_connectivity_watch(void* p, bool success) {
 }
 
 static void free_non_null(void* p) {
-  GPR_ASSERT(p != NULL);
+  GPR_ASSERT(p != nullptr);
   gpr_free(p);
 }
 
@@ -594,7 +594,7 @@ static call_state* g_active_call;
 static call_state* new_call(call_state* sibling, call_state_type type) {
   call_state* c = static_cast<call_state*>(gpr_malloc(sizeof(*c)));
   memset(c, 0, sizeof(*c));
-  if (sibling != NULL) {
+  if (sibling != nullptr) {
     c->next = sibling;
     c->prev = sibling->prev;
     c->next->prev = c->prev->next = c;
@@ -608,7 +608,7 @@ static call_state* new_call(call_state* sibling, call_state_type type) {
 static call_state* maybe_delete_call_state(call_state* call) {
   call_state* next = call->next;
 
-  if (call->call != NULL) return next;
+  if (call->call != nullptr) return next;
   if (call->pending_ops != 0) return next;
 
   if (call == g_active_call) {
@@ -682,7 +682,7 @@ static void read_metadata(input_stream* inp, size_t* count,
 
 static call_state* destroy_call(call_state* call) {
   grpc_call_unref(call->call);
-  call->call = NULL;
+  call->call = nullptr;
   return maybe_delete_call_state(call);
 }
 
@@ -691,7 +691,7 @@ static void finished_request_call(void* csp, bool success) {
   GPR_ASSERT(cs->pending_ops > 0);
   --cs->pending_ops;
   if (success) {
-    GPR_ASSERT(cs->call != NULL);
+    GPR_ASSERT(cs->call != nullptr);
     cs->type = SERVER;
   } else {
     maybe_delete_call_state(cs);
@@ -708,16 +708,16 @@ static void finished_batch(void* p, bool success) {
   --bi->cs->pending_ops;
   if ((bi->has_ops & (1u << GRPC_OP_RECV_MESSAGE)) &&
       (bi->cs->done_flags & DONE_FLAG_CALL_CLOSED)) {
-    GPR_ASSERT(bi->cs->recv_message == NULL);
+    GPR_ASSERT(bi->cs->recv_message == nullptr);
   }
   if ((bi->has_ops & (1u << GRPC_OP_RECV_MESSAGE) &&
-       bi->cs->recv_message != NULL)) {
+       bi->cs->recv_message != nullptr)) {
     grpc_byte_buffer_destroy(bi->cs->recv_message);
-    bi->cs->recv_message = NULL;
+    bi->cs->recv_message = nullptr;
   }
   if ((bi->has_ops & (1u << GRPC_OP_SEND_MESSAGE))) {
     grpc_byte_buffer_destroy(bi->cs->send_message);
-    bi->cs->send_message = NULL;
+    bi->cs->send_message = nullptr;
   }
   if ((bi->has_ops & (1u << GRPC_OP_RECV_STATUS_ON_CLIENT)) ||
       (bi->has_ops & (1u << GRPC_OP_RECV_CLOSE_ON_SERVER))) {
@@ -738,7 +738,7 @@ static validator* make_finished_batch_validator(call_state* cs,
 extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
   grpc_test_only_set_slice_hash_seed(0);
   char* grpc_trace_fuzzer = gpr_getenv("GRPC_TRACE_FUZZER");
-  if (squelch && grpc_trace_fuzzer == NULL) gpr_set_log_function(dont_log);
+  if (squelch && grpc_trace_fuzzer == nullptr) gpr_set_log_function(dont_log);
   gpr_free(grpc_trace_fuzzer);
   input_stream inp = {data, data + size};
   grpc_tcp_client_connect_impl = my_tcp_client_connect;
@@ -753,28 +753,28 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
   grpc_resolve_address = my_resolve_address;
   grpc_dns_lookup_ares = my_dns_lookup_ares;
 
-  GPR_ASSERT(g_channel == NULL);
-  GPR_ASSERT(g_server == NULL);
+  GPR_ASSERT(g_channel == nullptr);
+  GPR_ASSERT(g_server == nullptr);
 
   bool server_shutdown = false;
   int pending_server_shutdowns = 0;
   int pending_channel_watches = 0;
   int pending_pings = 0;
 
-  g_active_call = new_call(NULL, ROOT);
+  g_active_call = new_call(nullptr, ROOT);
   g_resource_quota = grpc_resource_quota_create("api_fuzzer");
 
-  grpc_completion_queue* cq = grpc_completion_queue_create_for_next(NULL);
+  grpc_completion_queue* cq = grpc_completion_queue_create_for_next(nullptr);
 
-  while (!is_eof(&inp) || g_channel != NULL || g_server != NULL ||
+  while (!is_eof(&inp) || g_channel != nullptr || g_server != nullptr ||
          pending_channel_watches > 0 || pending_pings > 0 ||
          g_active_call->type != ROOT || g_active_call->next != g_active_call) {
     if (is_eof(&inp)) {
-      if (g_channel != NULL) {
+      if (g_channel != nullptr) {
         grpc_channel_destroy(g_channel);
-        g_channel = NULL;
+        g_channel = nullptr;
       }
-      if (g_server != NULL) {
+      if (g_server != nullptr) {
         if (!server_shutdown) {
           grpc_server_shutdown_and_notify(
               g_server, cq,
@@ -784,12 +784,12 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
           pending_server_shutdowns++;
         } else if (pending_server_shutdowns == 0) {
           grpc_server_destroy(g_server);
-          g_server = NULL;
+          g_server = nullptr;
         }
       }
       call_state* s = g_active_call;
       do {
-        if (s->type != PENDING_SERVER && s->call != NULL) {
+        if (s->type != PENDING_SERVER && s->call != nullptr) {
           s = destroy_call(s);
         } else {
           s = s->next;
@@ -809,7 +809,7 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
       // tickle completion queue
       case 0: {
         grpc_event ev = grpc_completion_queue_next(
-            cq, gpr_inf_past(GPR_CLOCK_REALTIME), NULL);
+            cq, gpr_inf_past(GPR_CLOCK_REALTIME), nullptr);
         switch (ev.type) {
           case GRPC_OP_COMPLETE: {
             validator* v = static_cast<validator*>(ev.tag);
@@ -833,13 +833,13 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
       }
       // create an insecure channel
       case 2: {
-        if (g_channel == NULL) {
-          char* target = read_string(&inp, NULL);
+        if (g_channel == nullptr) {
+          char* target = read_string(&inp, nullptr);
           char* target_uri;
           gpr_asprintf(&target_uri, "dns:%s", target);
           grpc_channel_args* args = read_args(&inp);
-          g_channel = grpc_insecure_channel_create(target_uri, args, NULL);
-          GPR_ASSERT(g_channel != NULL);
+          g_channel = grpc_insecure_channel_create(target_uri, args, nullptr);
+          GPR_ASSERT(g_channel != nullptr);
           {
             grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
             grpc_channel_args_destroy(&exec_ctx, args);
@@ -854,9 +854,9 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
       }
       // destroy a channel
       case 3: {
-        if (g_channel != NULL) {
+        if (g_channel != nullptr) {
           grpc_channel_destroy(g_channel);
-          g_channel = NULL;
+          g_channel = nullptr;
         } else {
           end(&inp);
         }
@@ -864,16 +864,16 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
       }
       // bring up a server
       case 4: {
-        if (g_server == NULL) {
+        if (g_server == nullptr) {
           grpc_channel_args* args = read_args(&inp);
-          g_server = grpc_server_create(args, NULL);
-          GPR_ASSERT(g_server != NULL);
+          g_server = grpc_server_create(args, nullptr);
+          GPR_ASSERT(g_server != nullptr);
           {
             grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
             grpc_channel_args_destroy(&exec_ctx, args);
             grpc_exec_ctx_finish(&exec_ctx);
           }
-          grpc_server_register_completion_queue(g_server, cq, NULL);
+          grpc_server_register_completion_queue(g_server, cq, nullptr);
           grpc_server_start(g_server);
           server_shutdown = false;
           GPR_ASSERT(pending_server_shutdowns == 0);
@@ -884,7 +884,7 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
       }
       // begin server shutdown
       case 5: {
-        if (g_server != NULL) {
+        if (g_server != nullptr) {
           grpc_server_shutdown_and_notify(
               g_server, cq,
               create_validator(assert_success_and_decrement,
@@ -898,7 +898,7 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
       }
       // cancel all calls if shutdown
       case 6: {
-        if (g_server != NULL && server_shutdown) {
+        if (g_server != nullptr && server_shutdown) {
           grpc_server_cancel_all_calls(g_server);
         } else {
           end(&inp);
@@ -907,10 +907,10 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
       }
       // destroy server
       case 7: {
-        if (g_server != NULL && server_shutdown &&
+        if (g_server != nullptr && server_shutdown &&
             pending_server_shutdowns == 0) {
           grpc_server_destroy(g_server);
-          g_server = NULL;
+          g_server = nullptr;
         } else {
           end(&inp);
         }
@@ -918,7 +918,7 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
       }
       // check connectivity
       case 8: {
-        if (g_channel != NULL) {
+        if (g_channel != nullptr) {
           uint8_t try_to_connect = next_byte(&inp);
           if (try_to_connect == 0 || try_to_connect == 1) {
             grpc_channel_check_connectivity_state(g_channel, try_to_connect);
@@ -932,7 +932,7 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
       }
       // watch connectivity
       case 9: {
-        if (g_channel != NULL) {
+        if (g_channel != nullptr) {
           grpc_connectivity_state st =
               grpc_channel_check_connectivity_state(g_channel, 0);
           if (st != GRPC_CHANNEL_SHUTDOWN) {
@@ -954,10 +954,10 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
       // create a call
       case 10: {
         bool ok = true;
-        if (g_channel == NULL) ok = false;
-        grpc_call* parent_call = NULL;
+        if (g_channel == nullptr) ok = false;
+        grpc_call* parent_call = nullptr;
         if (g_active_call->type != ROOT) {
-          if (g_active_call->call == NULL || g_active_call->type == CLIENT) {
+          if (g_active_call->call == nullptr || g_active_call->type == CLIENT) {
             end(&inp);
             break;
           }
@@ -977,7 +977,7 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
           call_state* cs = new_call(g_active_call, CLIENT);
           cs->call =
               grpc_channel_create_call(g_channel, parent_call, propagation_mask,
-                                       cq, method, &host, deadline, NULL);
+                                       cq, method, &host, deadline, nullptr);
         } else {
           end(&inp);
         }
@@ -993,7 +993,7 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
       // queue some ops on a call
       case 12: {
         if (g_active_call->type == PENDING_SERVER ||
-            g_active_call->type == ROOT || g_active_call->call == NULL) {
+            g_active_call->type == ROOT || g_active_call->call == nullptr) {
           end(&inp);
           break;
         }
@@ -1026,7 +1026,7 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
               break;
             case GRPC_OP_SEND_MESSAGE:
               op->op = GRPC_OP_SEND_MESSAGE;
-              if (g_active_call->send_message != NULL) {
+              if (g_active_call->send_message != nullptr) {
                 ok = false;
               } else {
                 has_ops |= 1 << GRPC_OP_SEND_MESSAGE;
@@ -1078,14 +1078,14 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
                   &g_active_call->cancelled;
               break;
           }
-          op->reserved = NULL;
+          op->reserved = nullptr;
           op->flags = read_uint32(&inp);
         }
         if (ok) {
           validator* v = make_finished_batch_validator(g_active_call, has_ops);
           g_active_call->pending_ops++;
           grpc_call_error error =
-              grpc_call_start_batch(g_active_call->call, ops, num_ops, v, NULL);
+              grpc_call_start_batch(g_active_call->call, ops, num_ops, v, nullptr);
           if (error != GRPC_CALL_OK) {
             v->validate(v->arg, false);
             gpr_free(v);
@@ -1095,7 +1095,7 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
         }
         if (!ok && (has_ops & (1 << GRPC_OP_SEND_MESSAGE))) {
           grpc_byte_buffer_destroy(g_active_call->send_message);
-          g_active_call->send_message = NULL;
+          g_active_call->send_message = nullptr;
         }
         gpr_free(ops);
 
@@ -1103,8 +1103,8 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
       }
       // cancel current call
       case 13: {
-        if (g_active_call->type != ROOT && g_active_call->call != NULL) {
-          grpc_call_cancel(g_active_call->call, NULL);
+        if (g_active_call->type != ROOT && g_active_call->call != nullptr) {
+          grpc_call_cancel(g_active_call->call, nullptr);
         } else {
           end(&inp);
         }
@@ -1112,7 +1112,7 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
       }
       // get a calls peer
       case 14: {
-        if (g_active_call->type != ROOT && g_active_call->call != NULL) {
+        if (g_active_call->type != ROOT && g_active_call->call != nullptr) {
           free_non_null(grpc_call_get_peer(g_active_call->call));
         } else {
           end(&inp);
@@ -1121,7 +1121,7 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
       }
       // get a channels target
       case 15: {
-        if (g_channel != NULL) {
+        if (g_channel != nullptr) {
           free_non_null(grpc_channel_get_target(g_channel));
         } else {
           end(&inp);
@@ -1130,10 +1130,10 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
       }
       // send a ping on a channel
       case 16: {
-        if (g_channel != NULL) {
+        if (g_channel != nullptr) {
           pending_pings++;
           grpc_channel_ping(g_channel, cq,
-                            create_validator(decrement, &pending_pings), NULL);
+                            create_validator(decrement, &pending_pings), nullptr);
         } else {
           end(&inp);
         }
@@ -1141,21 +1141,21 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
       }
       // enable a tracer
       case 17: {
-        char* tracer = read_string(&inp, NULL);
+        char* tracer = read_string(&inp, nullptr);
         grpc_tracer_set_enabled(tracer, 1);
         gpr_free(tracer);
         break;
       }
       // disable a tracer
       case 18: {
-        char* tracer = read_string(&inp, NULL);
+        char* tracer = read_string(&inp, nullptr);
         grpc_tracer_set_enabled(tracer, 0);
         gpr_free(tracer);
         break;
       }
       // request a server call
       case 19: {
-        if (g_server == NULL) {
+        if (g_server == nullptr) {
           end(&inp);
           break;
         }
@@ -1175,7 +1175,7 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
       case 20: {
         if (g_active_call->type != ROOT &&
             g_active_call->type != PENDING_SERVER &&
-            g_active_call->call != NULL) {
+            g_active_call->call != nullptr) {
           destroy_call(g_active_call);
         } else {
           end(&inp);
@@ -1189,14 +1189,14 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
       }
       // create a secure channel
       case 22: {
-        if (g_channel == NULL) {
-          char* target = read_string(&inp, NULL);
+        if (g_channel == nullptr) {
+          char* target = read_string(&inp, nullptr);
           char* target_uri;
           gpr_asprintf(&target_uri, "dns:%s", target);
           grpc_channel_args* args = read_args(&inp);
           grpc_channel_credentials* creds = read_channel_creds(&inp);
-          g_channel = grpc_secure_channel_create(creds, target_uri, args, NULL);
-          GPR_ASSERT(g_channel != NULL);
+          g_channel = grpc_secure_channel_create(creds, target_uri, args, nullptr);
+          GPR_ASSERT(g_channel != nullptr);
           {
             grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
             grpc_channel_args_destroy(&exec_ctx, args);
@@ -1213,15 +1213,15 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
     }
   }
 
-  GPR_ASSERT(g_channel == NULL);
-  GPR_ASSERT(g_server == NULL);
+  GPR_ASSERT(g_channel == nullptr);
+  GPR_ASSERT(g_server == nullptr);
   GPR_ASSERT(g_active_call->type == ROOT);
   GPR_ASSERT(g_active_call->next == g_active_call);
   gpr_free(g_active_call);
 
   grpc_completion_queue_shutdown(cq);
   GPR_ASSERT(
-      grpc_completion_queue_next(cq, gpr_inf_past(GPR_CLOCK_REALTIME), NULL)
+      grpc_completion_queue_next(cq, gpr_inf_past(GPR_CLOCK_REALTIME), nullptr)
           .type == GRPC_QUEUE_SHUTDOWN);
   grpc_completion_queue_destroy(cq);
 
diff --git a/test/core/end2end/fuzzers/client_fuzzer.cc b/test/core/end2end/fuzzers/client_fuzzer.cc
index d90ec40a27..e4255a7a0a 100644
--- a/test/core/end2end/fuzzers/client_fuzzer.cc
+++ b/test/core/end2end/fuzzers/client_fuzzer.cc
@@ -52,21 +52,21 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
       grpc_mock_endpoint_create(discard_write, resource_quota);
   grpc_resource_quota_unref_internal(&exec_ctx, resource_quota);
 
-  grpc_completion_queue* cq = grpc_completion_queue_create_for_next(NULL);
+  grpc_completion_queue* cq = grpc_completion_queue_create_for_next(nullptr);
   grpc_transport* transport =
-      grpc_create_chttp2_transport(&exec_ctx, NULL, mock_endpoint, 1);
-  grpc_chttp2_transport_start_reading(&exec_ctx, transport, NULL);
+      grpc_create_chttp2_transport(&exec_ctx, nullptr, mock_endpoint, 1);
+  grpc_chttp2_transport_start_reading(&exec_ctx, transport, nullptr);
 
   grpc_channel* channel = grpc_channel_create(
-      &exec_ctx, "test-target", NULL, GRPC_CLIENT_DIRECT_CHANNEL, transport);
+      &exec_ctx, "test-target", nullptr, GRPC_CLIENT_DIRECT_CHANNEL, transport);
   grpc_slice host = grpc_slice_from_static_string("localhost");
   grpc_call* call = grpc_channel_create_call(
-      channel, NULL, 0, cq, grpc_slice_from_static_string("/foo"), &host,
-      gpr_inf_future(GPR_CLOCK_REALTIME), NULL);
+      channel, nullptr, 0, cq, grpc_slice_from_static_string("/foo"), &host,
+      gpr_inf_future(GPR_CLOCK_REALTIME), nullptr);
 
   grpc_metadata_array initial_metadata_recv;
   grpc_metadata_array_init(&initial_metadata_recv);
-  grpc_byte_buffer* response_payload_recv = NULL;
+  grpc_byte_buffer* response_payload_recv = nullptr;
   grpc_metadata_array trailing_metadata_recv;
   grpc_metadata_array_init(&trailing_metadata_recv);
   grpc_status_code status;
@@ -78,31 +78,31 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
   op->data.send_initial_metadata.count = 0;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_CLOSE_FROM_CLIENT;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_INITIAL_METADATA;
   op->data.recv_initial_metadata.recv_initial_metadata = &initial_metadata_recv;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_MESSAGE;
   op->data.recv_message.recv_message = &response_payload_recv;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_STATUS_ON_CLIENT;
   op->data.recv_status_on_client.trailing_metadata = &trailing_metadata_recv;
   op->data.recv_status_on_client.status = &status;
   op->data.recv_status_on_client.status_details = &details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   grpc_call_error error =
-      grpc_call_start_batch(call, ops, (size_t)(op - ops), tag(1), NULL);
+      grpc_call_start_batch(call, ops, (size_t)(op - ops), tag(1), nullptr);
   int requested_calls = 1;
   GPR_ASSERT(GRPC_CALL_OK == error);
 
@@ -113,7 +113,7 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
   grpc_event ev;
   while (1) {
     grpc_exec_ctx_flush(&exec_ctx);
-    ev = grpc_completion_queue_next(cq, gpr_inf_past(GPR_CLOCK_REALTIME), NULL);
+    ev = grpc_completion_queue_next(cq, gpr_inf_past(GPR_CLOCK_REALTIME), nullptr);
     switch (ev.type) {
       case GRPC_QUEUE_TIMEOUT:
         goto done;
@@ -127,15 +127,15 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
 
 done:
   if (requested_calls) {
-    grpc_call_cancel(call, NULL);
+    grpc_call_cancel(call, nullptr);
   }
   for (int i = 0; i < requested_calls; i++) {
-    ev = grpc_completion_queue_next(cq, gpr_inf_past(GPR_CLOCK_REALTIME), NULL);
+    ev = grpc_completion_queue_next(cq, gpr_inf_past(GPR_CLOCK_REALTIME), nullptr);
     GPR_ASSERT(ev.type == GRPC_OP_COMPLETE);
   }
   grpc_completion_queue_shutdown(cq);
   for (int i = 0; i < requested_calls; i++) {
-    ev = grpc_completion_queue_next(cq, gpr_inf_past(GPR_CLOCK_REALTIME), NULL);
+    ev = grpc_completion_queue_next(cq, gpr_inf_past(GPR_CLOCK_REALTIME), nullptr);
     GPR_ASSERT(ev.type == GRPC_QUEUE_SHUTDOWN);
   }
   grpc_call_unref(call);
@@ -144,7 +144,7 @@ done:
   grpc_metadata_array_destroy(&trailing_metadata_recv);
   grpc_slice_unref(details);
   grpc_channel_destroy(channel);
-  if (response_payload_recv != NULL) {
+  if (response_payload_recv != nullptr) {
     grpc_byte_buffer_destroy(response_payload_recv);
   }
   grpc_shutdown();
diff --git a/test/core/end2end/fuzzers/server_fuzzer.cc b/test/core/end2end/fuzzers/server_fuzzer.cc
index 87bccc70cd..177f6b47c4 100644
--- a/test/core/end2end/fuzzers/server_fuzzer.cc
+++ b/test/core/end2end/fuzzers/server_fuzzer.cc
@@ -53,19 +53,19 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
       &exec_ctx, mock_endpoint,
       grpc_slice_from_copied_buffer((const char*)data, size));
 
-  grpc_server* server = grpc_server_create(NULL, NULL);
-  grpc_completion_queue* cq = grpc_completion_queue_create_for_next(NULL);
-  grpc_server_register_completion_queue(server, cq, NULL);
+  grpc_server* server = grpc_server_create(nullptr, nullptr);
+  grpc_completion_queue* cq = grpc_completion_queue_create_for_next(nullptr);
+  grpc_server_register_completion_queue(server, cq, nullptr);
   // TODO(ctiller): add registered methods (one for POST, one for PUT)
   // void *registered_method =
   //    grpc_server_register_method(server, "/reg", NULL, 0);
   grpc_server_start(server);
   grpc_transport* transport =
-      grpc_create_chttp2_transport(&exec_ctx, NULL, mock_endpoint, 0);
-  grpc_server_setup_transport(&exec_ctx, server, transport, NULL, NULL);
-  grpc_chttp2_transport_start_reading(&exec_ctx, transport, NULL);
+      grpc_create_chttp2_transport(&exec_ctx, nullptr, mock_endpoint, 0);
+  grpc_server_setup_transport(&exec_ctx, server, transport, nullptr, nullptr);
+  grpc_chttp2_transport_start_reading(&exec_ctx, transport, nullptr);
 
-  grpc_call* call1 = NULL;
+  grpc_call* call1 = nullptr;
   grpc_call_details call_details1;
   grpc_metadata_array request_metadata1;
   grpc_call_details_init(&call_details1);
@@ -80,7 +80,7 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
   grpc_event ev;
   while (1) {
     grpc_exec_ctx_flush(&exec_ctx);
-    ev = grpc_completion_queue_next(cq, gpr_inf_past(GPR_CLOCK_REALTIME), NULL);
+    ev = grpc_completion_queue_next(cq, gpr_inf_past(GPR_CLOCK_REALTIME), nullptr);
     switch (ev.type) {
       case GRPC_QUEUE_TIMEOUT:
         goto done;
@@ -97,18 +97,18 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
   }
 
 done:
-  if (call1 != NULL) grpc_call_unref(call1);
+  if (call1 != nullptr) grpc_call_unref(call1);
   grpc_call_details_destroy(&call_details1);
   grpc_metadata_array_destroy(&request_metadata1);
   grpc_server_shutdown_and_notify(server, cq, tag(0xdead));
   grpc_server_cancel_all_calls(server);
   for (int i = 0; i <= requested_calls; i++) {
-    ev = grpc_completion_queue_next(cq, gpr_inf_past(GPR_CLOCK_REALTIME), NULL);
+    ev = grpc_completion_queue_next(cq, gpr_inf_past(GPR_CLOCK_REALTIME), nullptr);
     GPR_ASSERT(ev.type == GRPC_OP_COMPLETE);
   }
   grpc_completion_queue_shutdown(cq);
   for (int i = 0; i <= requested_calls; i++) {
-    ev = grpc_completion_queue_next(cq, gpr_inf_past(GPR_CLOCK_REALTIME), NULL);
+    ev = grpc_completion_queue_next(cq, gpr_inf_past(GPR_CLOCK_REALTIME), nullptr);
     GPR_ASSERT(ev.type == GRPC_QUEUE_SHUTDOWN);
   }
   grpc_server_destroy(server);
diff --git a/test/core/end2end/goaway_server_test.cc b/test/core/end2end/goaway_server_test.cc
index 12a966d05a..1d37848b3f 100644
--- a/test/core/end2end/goaway_server_test.cc
+++ b/test/core/end2end/goaway_server_test.cc
@@ -106,19 +106,19 @@ static grpc_ares_request* my_dns_lookup_ares(
     gpr_mu_unlock(&g_mu);
     error = GRPC_ERROR_CREATE_FROM_STATIC_STRING("Forced Failure");
   } else {
-    *lb_addrs = grpc_lb_addresses_create(1, NULL);
+    *lb_addrs = grpc_lb_addresses_create(1, nullptr);
     struct sockaddr_in* sa = static_cast<struct sockaddr_in*>(
         gpr_zalloc(sizeof(struct sockaddr_in)));
     sa->sin_family = AF_INET;
     sa->sin_addr.s_addr = htonl(0x7f000001);
     sa->sin_port = htons((uint16_t)g_resolve_port);
-    grpc_lb_addresses_set_address(*lb_addrs, 0, sa, sizeof(*sa), false, NULL,
-                                  NULL);
+    grpc_lb_addresses_set_address(*lb_addrs, 0, sa, sizeof(*sa), false, nullptr,
+                                  nullptr);
     gpr_free(sa);
     gpr_mu_unlock(&g_mu);
   }
   GRPC_CLOSURE_SCHED(exec_ctx, on_done, error);
-  return NULL;
+  return nullptr;
 }
 
 int main(int argc, char** argv) {
@@ -157,7 +157,7 @@ int main(int argc, char** argv) {
   grpc_metadata_array_init(&request_metadata2);
   grpc_call_details_init(&request_details2);
 
-  cq = grpc_completion_queue_create_for_next(NULL);
+  cq = grpc_completion_queue_create_for_next(nullptr);
   cqv = cq_verifier_create(cq);
 
   /* reserve two ports */
@@ -176,24 +176,24 @@ int main(int argc, char** argv) {
   client_args.num_args = 1;
 
   /* create a channel that picks first amongst the servers */
-  grpc_channel* chan = grpc_insecure_channel_create("test", &client_args, NULL);
+  grpc_channel* chan = grpc_insecure_channel_create("test", &client_args, nullptr);
   /* and an initial call to them */
   grpc_slice host = grpc_slice_from_static_string("127.0.0.1");
   grpc_call* call1 =
-      grpc_channel_create_call(chan, NULL, GRPC_PROPAGATE_DEFAULTS, cq,
+      grpc_channel_create_call(chan, nullptr, GRPC_PROPAGATE_DEFAULTS, cq,
                                grpc_slice_from_static_string("/foo"), &host,
-                               grpc_timeout_seconds_to_deadline(20), NULL);
+                               grpc_timeout_seconds_to_deadline(20), nullptr);
   /* send initial metadata to probe connectivity */
   memset(ops, 0, sizeof(ops));
   op = ops;
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
   op->data.send_initial_metadata.count = 0;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   GPR_ASSERT(GRPC_CALL_OK == grpc_call_start_batch(call1, ops,
                                                    (size_t)(op - ops),
-                                                   tag(0x101), NULL));
+                                                   tag(0x101), nullptr));
   /* and receive status to probe termination */
   memset(ops, 0, sizeof(ops));
   op = ops;
@@ -202,17 +202,17 @@ int main(int argc, char** argv) {
   op->data.recv_status_on_client.status = &status1;
   op->data.recv_status_on_client.status_details = &details1;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   GPR_ASSERT(GRPC_CALL_OK == grpc_call_start_batch(call1, ops,
                                                    (size_t)(op - ops),
-                                                   tag(0x102), NULL));
+                                                   tag(0x102), nullptr));
 
   /* bring a server up on the first port */
-  grpc_server* server1 = grpc_server_create(NULL, NULL);
+  grpc_server* server1 = grpc_server_create(nullptr, nullptr);
   gpr_asprintf(&addr, "127.0.0.1:%d", port1);
   grpc_server_add_insecure_http2_port(server1, addr);
-  grpc_server_register_completion_queue(server1, cq, NULL);
+  grpc_server_register_completion_queue(server1, cq, nullptr);
   gpr_free(addr);
   grpc_server_start(server1);
 
@@ -244,7 +244,7 @@ int main(int argc, char** argv) {
   op++;
   GPR_ASSERT(GRPC_CALL_OK == grpc_call_start_batch(server_call1, ops,
                                                    (size_t)(op - ops),
-                                                   tag(0x302), NULL));
+                                                   tag(0x302), nullptr));
 
   /* shutdown first server:
    * we should see a connectivity change and then nothing */
@@ -256,20 +256,20 @@ int main(int argc, char** argv) {
 
   /* and a new call: should go through to server2 when we start it */
   grpc_call* call2 =
-      grpc_channel_create_call(chan, NULL, GRPC_PROPAGATE_DEFAULTS, cq,
+      grpc_channel_create_call(chan, nullptr, GRPC_PROPAGATE_DEFAULTS, cq,
                                grpc_slice_from_static_string("/foo"), &host,
-                               grpc_timeout_seconds_to_deadline(20), NULL);
+                               grpc_timeout_seconds_to_deadline(20), nullptr);
   /* send initial metadata to probe connectivity */
   memset(ops, 0, sizeof(ops));
   op = ops;
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
   op->data.send_initial_metadata.count = 0;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   GPR_ASSERT(GRPC_CALL_OK == grpc_call_start_batch(call2, ops,
                                                    (size_t)(op - ops),
-                                                   tag(0x201), NULL));
+                                                   tag(0x201), nullptr));
   /* and receive status to probe termination */
   memset(ops, 0, sizeof(ops));
   op = ops;
@@ -278,18 +278,18 @@ int main(int argc, char** argv) {
   op->data.recv_status_on_client.status = &status2;
   op->data.recv_status_on_client.status_details = &details2;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   GPR_ASSERT(GRPC_CALL_OK == grpc_call_start_batch(call2, ops,
                                                    (size_t)(op - ops),
-                                                   tag(0x202), NULL));
+                                                   tag(0x202), nullptr));
 
   /* and bring up second server */
   set_resolve_port(port2);
-  grpc_server* server2 = grpc_server_create(NULL, NULL);
+  grpc_server* server2 = grpc_server_create(nullptr, nullptr);
   gpr_asprintf(&addr, "127.0.0.1:%d", port2);
   grpc_server_add_insecure_http2_port(server2, addr);
-  grpc_server_register_completion_queue(server2, cq, NULL);
+  grpc_server_register_completion_queue(server2, cq, nullptr);
   gpr_free(addr);
   grpc_server_start(server2);
 
@@ -313,14 +313,14 @@ int main(int argc, char** argv) {
   op++;
   GPR_ASSERT(GRPC_CALL_OK == grpc_call_start_batch(server_call2, ops,
                                                    (size_t)(op - ops),
-                                                   tag(0x402), NULL));
+                                                   tag(0x402), nullptr));
 
   /* shutdown second server: we should see nothing */
   grpc_server_shutdown_and_notify(server2, cq, tag(0xdead2));
   cq_verify_empty(cqv);
 
-  grpc_call_cancel(call1, NULL);
-  grpc_call_cancel(call2, NULL);
+  grpc_call_cancel(call1, nullptr);
+  grpc_call_cancel(call2, nullptr);
 
   /* now everything else should finish */
   CQ_EXPECT_COMPLETION(cqv, tag(0x102), 1);
diff --git a/test/core/end2end/h2_ssl_cert_test.cc b/test/core/end2end/h2_ssl_cert_test.cc
index 8994b63e5f..9a98c07158 100644
--- a/test/core/end2end/h2_ssl_cert_test.cc
+++ b/test/core/end2end/h2_ssl_cert_test.cc
@@ -56,8 +56,8 @@ static grpc_end2end_test_fixture chttp2_create_fixture_secure_fullstack(
   gpr_join_host_port(&ffd->localaddr, "localhost", port);
 
   f.fixture_data = ffd;
-  f.cq = grpc_completion_queue_create_for_next(NULL);
-  f.shutdown_cq = grpc_completion_queue_create_for_pluck(NULL);
+  f.cq = grpc_completion_queue_create_for_next(nullptr);
+  f.shutdown_cq = grpc_completion_queue_create_for_pluck(nullptr);
 
   return f;
 }
@@ -66,8 +66,8 @@ static void process_auth_failure(void* state, grpc_auth_context* ctx,
                                  const grpc_metadata* md, size_t md_count,
                                  grpc_process_auth_metadata_done_cb cb,
                                  void* user_data) {
-  GPR_ASSERT(state == NULL);
-  cb(user_data, NULL, 0, NULL, 0, GRPC_STATUS_UNAUTHENTICATED, NULL);
+  GPR_ASSERT(state == nullptr);
+  cb(user_data, nullptr, 0, nullptr, 0, GRPC_STATUS_UNAUTHENTICATED, nullptr);
 }
 
 static void chttp2_init_client_secure_fullstack(
@@ -76,8 +76,8 @@ static void chttp2_init_client_secure_fullstack(
   fullstack_secure_fixture_data* ffd =
       static_cast<fullstack_secure_fixture_data*>(f->fixture_data);
   f->client =
-      grpc_secure_channel_create(creds, ffd->localaddr, client_args, NULL);
-  GPR_ASSERT(f->client != NULL);
+      grpc_secure_channel_create(creds, ffd->localaddr, client_args, nullptr);
+  GPR_ASSERT(f->client != nullptr);
   grpc_channel_credentials_release(creds);
 }
 
@@ -89,8 +89,8 @@ static void chttp2_init_server_secure_fullstack(
   if (f->server) {
     grpc_server_destroy(f->server);
   }
-  f->server = grpc_server_create(server_args, NULL);
-  grpc_server_register_completion_queue(f->server, f->cq, NULL);
+  f->server = grpc_server_create(server_args, nullptr);
+  grpc_server_register_completion_queue(f->server, f->cq, nullptr);
   GPR_ASSERT(grpc_server_add_secure_http2_port(f->server, ffd->localaddr,
                                                server_creds));
   grpc_server_credentials_release(server_creds);
@@ -106,7 +106,7 @@ void chttp2_tear_down_secure_fullstack(grpc_end2end_test_fixture* f) {
 
 static int fail_server_auth_check(grpc_channel_args* server_args) {
   size_t i;
-  if (server_args == NULL) return 0;
+  if (server_args == nullptr) return 0;
   for (i = 0; i < server_args->num_args; i++) {
     if (strcmp(server_args->args[i].key, FAIL_AUTH_CHECK_SERVER_ARG_NAME) ==
         0) {
@@ -267,7 +267,7 @@ static gpr_timespec five_seconds_time(void) { return n_seconds_time(5); }
 static void drain_cq(grpc_completion_queue* cq) {
   grpc_event ev;
   do {
-    ev = grpc_completion_queue_next(cq, five_seconds_time(), NULL);
+    ev = grpc_completion_queue_next(cq, five_seconds_time(), nullptr);
   } while (ev.type != GRPC_QUEUE_SHUTDOWN);
 }
 
@@ -276,16 +276,16 @@ static void shutdown_server(grpc_end2end_test_fixture* f) {
   grpc_server_shutdown_and_notify(f->server, f->shutdown_cq, tag(1000));
   GPR_ASSERT(grpc_completion_queue_pluck(f->shutdown_cq, tag(1000),
                                          grpc_timeout_seconds_to_deadline(5),
-                                         NULL)
+                                         nullptr)
                  .type == GRPC_OP_COMPLETE);
   grpc_server_destroy(f->server);
-  f->server = NULL;
+  f->server = nullptr;
 }
 
 static void shutdown_client(grpc_end2end_test_fixture* f) {
   if (!f->client) return;
   grpc_channel_destroy(f->client);
-  f->client = NULL;
+  f->client = nullptr;
 }
 
 static void end_test(grpc_end2end_test_fixture* f) {
@@ -308,9 +308,9 @@ static void simple_request_body(grpc_end2end_test_fixture f,
   grpc_call_error error;
 
   grpc_slice host = grpc_slice_from_static_string("foo.test.google.fr:1234");
-  c = grpc_channel_create_call(f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+  c = grpc_channel_create_call(f.client, nullptr, GRPC_PROPAGATE_DEFAULTS, f.cq,
                                grpc_slice_from_static_string("/foo"), &host,
-                               deadline, NULL);
+                               deadline, nullptr);
   GPR_ASSERT(c);
 
   memset(ops, 0, sizeof(ops));
@@ -318,9 +318,9 @@ static void simple_request_body(grpc_end2end_test_fixture f,
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
   op->data.send_initial_metadata.count = 0;
   op->flags = GRPC_INITIAL_METADATA_WAIT_FOR_READY;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), NULL);
+  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   CQ_EXPECT_COMPLETION(cqv, tag(1), expected_result == SUCCESS);
@@ -367,8 +367,8 @@ int main(int argc, char** argv) {
   /* Set the SSL roots env var. */
   roots_file =
       gpr_tmpfile("chttp2_simple_ssl_cert_fullstack_test", &roots_filename);
-  GPR_ASSERT(roots_filename != NULL);
-  GPR_ASSERT(roots_file != NULL);
+  GPR_ASSERT(roots_filename != nullptr);
+  GPR_ASSERT(roots_file != nullptr);
   GPR_ASSERT(fwrite(test_root_cert, 1, roots_size, roots_file) == roots_size);
   fclose(roots_file);
   gpr_setenv(GRPC_DEFAULT_SSL_ROOTS_FILE_PATH_ENV_VAR, roots_filename);
diff --git a/test/core/end2end/invalid_call_argument_test.cc b/test/core/end2end/invalid_call_argument_test.cc
index c310a0e9ba..ff7f710095 100644
--- a/test/core/end2end/invalid_call_argument_test.cc
+++ b/test/core/end2end/invalid_call_argument_test.cc
@@ -60,7 +60,7 @@ static void prepare_test(int is_client) {
   grpc_metadata_array_init(&g_state.initial_metadata_recv);
   grpc_metadata_array_init(&g_state.trailing_metadata_recv);
   g_state.deadline = grpc_timeout_seconds_to_deadline(5);
-  g_state.cq = grpc_completion_queue_create_for_next(NULL);
+  g_state.cq = grpc_completion_queue_create_for_next(nullptr);
   g_state.cqv = cq_verifier_create(g_state.cq);
   g_state.details = grpc_empty_slice();
   memset(g_state.ops, 0, sizeof(g_state.ops));
@@ -68,36 +68,36 @@ static void prepare_test(int is_client) {
   if (is_client) {
     /* create a call, channel to a non existant server */
     g_state.chan =
-        grpc_insecure_channel_create("nonexistant:54321", NULL, NULL);
+        grpc_insecure_channel_create("nonexistant:54321", nullptr, nullptr);
     grpc_slice host = grpc_slice_from_static_string("nonexistant");
     g_state.call = grpc_channel_create_call(
-        g_state.chan, NULL, GRPC_PROPAGATE_DEFAULTS, g_state.cq,
-        grpc_slice_from_static_string("/Foo"), &host, g_state.deadline, NULL);
+        g_state.chan, nullptr, GRPC_PROPAGATE_DEFAULTS, g_state.cq,
+        grpc_slice_from_static_string("/Foo"), &host, g_state.deadline, nullptr);
   } else {
-    g_state.server = grpc_server_create(NULL, NULL);
-    grpc_server_register_completion_queue(g_state.server, g_state.cq, NULL);
+    g_state.server = grpc_server_create(nullptr, nullptr);
+    grpc_server_register_completion_queue(g_state.server, g_state.cq, nullptr);
     gpr_join_host_port(&server_hostport, "0.0.0.0", port);
     grpc_server_add_insecure_http2_port(g_state.server, server_hostport);
     grpc_server_start(g_state.server);
     gpr_free(server_hostport);
     gpr_join_host_port(&server_hostport, "localhost", port);
-    g_state.chan = grpc_insecure_channel_create(server_hostport, NULL, NULL);
+    g_state.chan = grpc_insecure_channel_create(server_hostport, nullptr, nullptr);
     gpr_free(server_hostport);
     grpc_slice host = grpc_slice_from_static_string("bar");
     g_state.call = grpc_channel_create_call(
-        g_state.chan, NULL, GRPC_PROPAGATE_DEFAULTS, g_state.cq,
-        grpc_slice_from_static_string("/Foo"), &host, g_state.deadline, NULL);
+        g_state.chan, nullptr, GRPC_PROPAGATE_DEFAULTS, g_state.cq,
+        grpc_slice_from_static_string("/Foo"), &host, g_state.deadline, nullptr);
     grpc_metadata_array_init(&g_state.server_initial_metadata_recv);
     grpc_call_details_init(&g_state.call_details);
     op = g_state.ops;
     op->op = GRPC_OP_SEND_INITIAL_METADATA;
     op->data.send_initial_metadata.count = 0;
     op->flags = GRPC_INITIAL_METADATA_WAIT_FOR_READY;
-    op->reserved = NULL;
+    op->reserved = nullptr;
     op++;
     GPR_ASSERT(GRPC_CALL_OK == grpc_call_start_batch(g_state.call, g_state.ops,
                                                      (size_t)(op - g_state.ops),
-                                                     tag(1), NULL));
+                                                     tag(1), nullptr));
     GPR_ASSERT(GRPC_CALL_OK ==
                grpc_server_request_call(g_state.server, &g_state.server_call,
                                         &g_state.call_details,
@@ -119,12 +119,12 @@ static void cleanup_test() {
   grpc_metadata_array_destroy(&g_state.trailing_metadata_recv);
 
   if (!g_state.is_client) {
-    shutdown_cq = grpc_completion_queue_create_for_pluck(NULL);
+    shutdown_cq = grpc_completion_queue_create_for_pluck(nullptr);
     grpc_call_unref(g_state.server_call);
     grpc_server_shutdown_and_notify(g_state.server, shutdown_cq, tag(1000));
     GPR_ASSERT(grpc_completion_queue_pluck(shutdown_cq, tag(1000),
                                            grpc_timeout_seconds_to_deadline(5),
-                                           NULL)
+                                           nullptr)
                    .type == GRPC_OP_COMPLETE);
     grpc_completion_queue_destroy(shutdown_cq);
     grpc_server_destroy(g_state.server);
@@ -133,7 +133,7 @@ static void cleanup_test() {
   }
   grpc_completion_queue_shutdown(g_state.cq);
   while (grpc_completion_queue_next(g_state.cq,
-                                    gpr_inf_future(GPR_CLOCK_REALTIME), NULL)
+                                    gpr_inf_future(GPR_CLOCK_REALTIME), nullptr)
              .type != GRPC_QUEUE_SHUTDOWN)
     ;
   grpc_completion_queue_destroy(g_state.cq);
@@ -144,7 +144,7 @@ static void test_non_null_reserved_on_start_batch() {
 
   prepare_test(1);
   GPR_ASSERT(GRPC_CALL_ERROR ==
-             grpc_call_start_batch(g_state.call, NULL, 0, NULL, tag(1)));
+             grpc_call_start_batch(g_state.call, nullptr, 0, nullptr, tag(1)));
   cleanup_test();
 }
 
@@ -162,7 +162,7 @@ static void test_non_null_reserved_on_op() {
   op++;
   GPR_ASSERT(GRPC_CALL_ERROR ==
              grpc_call_start_batch(g_state.call, g_state.ops,
-                                   (size_t)(op - g_state.ops), tag(1), NULL));
+                                   (size_t)(op - g_state.ops), tag(1), nullptr));
   cleanup_test();
 }
 
@@ -176,11 +176,11 @@ static void test_send_initial_metadata_more_than_once() {
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
   op->data.send_initial_metadata.count = 0;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   GPR_ASSERT(GRPC_CALL_OK == grpc_call_start_batch(g_state.call, g_state.ops,
                                                    (size_t)(op - g_state.ops),
-                                                   tag(1), NULL));
+                                                   tag(1), nullptr));
   CQ_EXPECT_COMPLETION(g_state.cqv, tag(1), 0);
   cq_verify(g_state.cqv);
 
@@ -188,11 +188,11 @@ static void test_send_initial_metadata_more_than_once() {
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
   op->data.send_initial_metadata.count = 0;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   GPR_ASSERT(GRPC_CALL_ERROR_TOO_MANY_OPERATIONS ==
              grpc_call_start_batch(g_state.call, g_state.ops,
-                                   (size_t)(op - g_state.ops), tag(1), NULL));
+                                   (size_t)(op - g_state.ops), tag(1), nullptr));
   cleanup_test();
 }
 
@@ -206,11 +206,11 @@ static void test_too_many_metadata() {
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
   op->data.send_initial_metadata.count = (size_t)INT_MAX + 1;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   GPR_ASSERT(GRPC_CALL_ERROR_INVALID_METADATA ==
              grpc_call_start_batch(g_state.call, g_state.ops,
-                                   (size_t)(op - g_state.ops), tag(1), NULL));
+                                   (size_t)(op - g_state.ops), tag(1), nullptr));
   cleanup_test();
 }
 
@@ -224,16 +224,16 @@ static void test_send_null_message() {
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
   op->data.send_initial_metadata.count = 0;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_MESSAGE;
-  op->data.send_message.send_message = NULL;
+  op->data.send_message.send_message = nullptr;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   GPR_ASSERT(GRPC_CALL_ERROR_INVALID_MESSAGE ==
              grpc_call_start_batch(g_state.call, g_state.ops,
-                                   (size_t)(op - g_state.ops), tag(1), NULL));
+                                   (size_t)(op - g_state.ops), tag(1), nullptr));
   cleanup_test();
 }
 
@@ -250,21 +250,21 @@ static void test_send_messages_at_the_same_time() {
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
   op->data.send_initial_metadata.count = 0;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_MESSAGE;
   op->data.send_message.send_message = request_payload;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_MESSAGE;
   op->data.send_message.send_message = static_cast<grpc_byte_buffer*>(tag(2));
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   GPR_ASSERT(GRPC_CALL_ERROR_TOO_MANY_OPERATIONS ==
              grpc_call_start_batch(g_state.call, g_state.ops,
-                                   (size_t)(op - g_state.ops), tag(1), NULL));
+                                   (size_t)(op - g_state.ops), tag(1), nullptr));
   grpc_byte_buffer_destroy(request_payload);
   cleanup_test();
 }
@@ -282,11 +282,11 @@ static void test_send_server_status_from_client() {
   grpc_slice status_details = grpc_slice_from_static_string("xyz");
   op->data.send_status_from_server.status_details = &status_details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   GPR_ASSERT(GRPC_CALL_ERROR_NOT_ON_CLIENT ==
              grpc_call_start_batch(g_state.call, g_state.ops,
-                                   (size_t)(op - g_state.ops), tag(1), NULL));
+                                   (size_t)(op - g_state.ops), tag(1), nullptr));
   cleanup_test();
 }
 
@@ -300,11 +300,11 @@ static void test_receive_initial_metadata_twice_at_client() {
   op->data.recv_initial_metadata.recv_initial_metadata =
       &g_state.initial_metadata_recv;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   GPR_ASSERT(GRPC_CALL_OK == grpc_call_start_batch(g_state.call, g_state.ops,
                                                    (size_t)(op - g_state.ops),
-                                                   tag(1), NULL));
+                                                   tag(1), nullptr));
   CQ_EXPECT_COMPLETION(g_state.cqv, tag(1), 0);
   cq_verify(g_state.cqv);
   op = g_state.ops;
@@ -312,11 +312,11 @@ static void test_receive_initial_metadata_twice_at_client() {
   op->data.recv_initial_metadata.recv_initial_metadata =
       &g_state.initial_metadata_recv;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   GPR_ASSERT(GRPC_CALL_ERROR_TOO_MANY_OPERATIONS ==
              grpc_call_start_batch(g_state.call, g_state.ops,
-                                   (size_t)(op - g_state.ops), tag(1), NULL));
+                                   (size_t)(op - g_state.ops), tag(1), nullptr));
   cleanup_test();
 }
 
@@ -324,17 +324,17 @@ static void test_receive_message_with_invalid_flags() {
   gpr_log(GPR_INFO, "test_receive_message_with_invalid_flags");
 
   grpc_op* op;
-  grpc_byte_buffer* payload = NULL;
+  grpc_byte_buffer* payload = nullptr;
   prepare_test(1);
   op = g_state.ops;
   op->op = GRPC_OP_RECV_MESSAGE;
   op->data.recv_message.recv_message = &payload;
   op->flags = 1;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   GPR_ASSERT(GRPC_CALL_ERROR_INVALID_FLAGS ==
              grpc_call_start_batch(g_state.call, g_state.ops,
-                                   (size_t)(op - g_state.ops), tag(1), NULL));
+                                   (size_t)(op - g_state.ops), tag(1), nullptr));
   cleanup_test();
 }
 
@@ -342,22 +342,22 @@ static void test_receive_two_messages_at_the_same_time() {
   gpr_log(GPR_INFO, "test_receive_two_messages_at_the_same_time");
 
   grpc_op* op;
-  grpc_byte_buffer* payload = NULL;
+  grpc_byte_buffer* payload = nullptr;
   prepare_test(1);
   op = g_state.ops;
   op->op = GRPC_OP_RECV_MESSAGE;
   op->data.recv_message.recv_message = &payload;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_MESSAGE;
   op->data.recv_message.recv_message = &payload;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   GPR_ASSERT(GRPC_CALL_ERROR_TOO_MANY_OPERATIONS ==
              grpc_call_start_batch(g_state.call, g_state.ops,
-                                   (size_t)(op - g_state.ops), tag(1), NULL));
+                                   (size_t)(op - g_state.ops), tag(1), nullptr));
   cleanup_test();
 }
 
@@ -369,13 +369,13 @@ static void test_recv_close_on_server_from_client() {
 
   op = g_state.ops;
   op->op = GRPC_OP_RECV_CLOSE_ON_SERVER;
-  op->data.recv_close_on_server.cancelled = NULL;
+  op->data.recv_close_on_server.cancelled = nullptr;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   GPR_ASSERT(GRPC_CALL_ERROR_NOT_ON_CLIENT ==
              grpc_call_start_batch(g_state.call, g_state.ops,
-                                   (size_t)(op - g_state.ops), tag(1), NULL));
+                                   (size_t)(op - g_state.ops), tag(1), nullptr));
   cleanup_test();
 }
 
@@ -392,25 +392,25 @@ static void test_recv_status_on_client_twice() {
   op->data.recv_status_on_client.status = &g_state.status;
   op->data.recv_status_on_client.status_details = &g_state.details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   GPR_ASSERT(GRPC_CALL_OK == grpc_call_start_batch(g_state.call, g_state.ops,
                                                    (size_t)(op - g_state.ops),
-                                                   tag(1), NULL));
+                                                   tag(1), nullptr));
   CQ_EXPECT_COMPLETION(g_state.cqv, tag(1), 1);
   cq_verify(g_state.cqv);
 
   op = g_state.ops;
   op->op = GRPC_OP_RECV_STATUS_ON_CLIENT;
-  op->data.recv_status_on_client.trailing_metadata = NULL;
-  op->data.recv_status_on_client.status = NULL;
-  op->data.recv_status_on_client.status_details = NULL;
+  op->data.recv_status_on_client.trailing_metadata = nullptr;
+  op->data.recv_status_on_client.status = nullptr;
+  op->data.recv_status_on_client.status_details = nullptr;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   GPR_ASSERT(GRPC_CALL_ERROR_TOO_MANY_OPERATIONS ==
              grpc_call_start_batch(g_state.call, g_state.ops,
-                                   (size_t)(op - g_state.ops), tag(1), NULL));
+                                   (size_t)(op - g_state.ops), tag(1), nullptr));
   cleanup_test();
 }
 
@@ -423,11 +423,11 @@ static void test_send_close_from_client_on_server() {
   op = g_state.ops;
   op->op = GRPC_OP_SEND_CLOSE_FROM_CLIENT;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   GPR_ASSERT(GRPC_CALL_ERROR_NOT_ON_SERVER ==
              grpc_call_start_batch(g_state.server_call, g_state.ops,
-                                   (size_t)(op - g_state.ops), tag(2), NULL));
+                                   (size_t)(op - g_state.ops), tag(2), nullptr));
   cleanup_test();
 }
 
@@ -444,11 +444,11 @@ static void test_recv_status_on_client_from_server() {
   op->data.recv_status_on_client.status = &g_state.status;
   op->data.recv_status_on_client.status_details = &g_state.details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   GPR_ASSERT(GRPC_CALL_ERROR_NOT_ON_SERVER ==
              grpc_call_start_batch(g_state.server_call, g_state.ops,
-                                   (size_t)(op - g_state.ops), tag(2), NULL));
+                                   (size_t)(op - g_state.ops), tag(2), nullptr));
   cleanup_test();
 }
 
@@ -465,11 +465,11 @@ static void test_send_status_from_server_with_invalid_flags() {
   grpc_slice status_details = grpc_slice_from_static_string("xyz");
   op->data.send_status_from_server.status_details = &status_details;
   op->flags = 1;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   GPR_ASSERT(GRPC_CALL_ERROR_INVALID_FLAGS ==
              grpc_call_start_batch(g_state.server_call, g_state.ops,
-                                   (size_t)(op - g_state.ops), tag(2), NULL));
+                                   (size_t)(op - g_state.ops), tag(2), nullptr));
   cleanup_test();
 }
 
@@ -487,11 +487,11 @@ static void test_too_many_trailing_metadata() {
   grpc_slice status_details = grpc_slice_from_static_string("xyz");
   op->data.send_status_from_server.status_details = &status_details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   GPR_ASSERT(GRPC_CALL_ERROR_INVALID_METADATA ==
              grpc_call_start_batch(g_state.server_call, g_state.ops,
-                                   (size_t)(op - g_state.ops), tag(2), NULL));
+                                   (size_t)(op - g_state.ops), tag(2), nullptr));
   cleanup_test();
 }
 
@@ -508,18 +508,18 @@ static void test_send_server_status_twice() {
   grpc_slice status_details = grpc_slice_from_static_string("xyz");
   op->data.send_status_from_server.status_details = &status_details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_STATUS_FROM_SERVER;
   op->data.send_status_from_server.trailing_metadata_count = 0;
   op->data.send_status_from_server.status = GRPC_STATUS_UNIMPLEMENTED;
   op->data.send_status_from_server.status_details = &status_details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   GPR_ASSERT(GRPC_CALL_ERROR_TOO_MANY_OPERATIONS ==
              grpc_call_start_batch(g_state.server_call, g_state.ops,
-                                   (size_t)(op - g_state.ops), tag(2), NULL));
+                                   (size_t)(op - g_state.ops), tag(2), nullptr));
   cleanup_test();
 }
 
@@ -531,13 +531,13 @@ static void test_recv_close_on_server_with_invalid_flags() {
 
   op = g_state.ops;
   op->op = GRPC_OP_RECV_CLOSE_ON_SERVER;
-  op->data.recv_close_on_server.cancelled = NULL;
+  op->data.recv_close_on_server.cancelled = nullptr;
   op->flags = 1;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   GPR_ASSERT(GRPC_CALL_ERROR_INVALID_FLAGS ==
              grpc_call_start_batch(g_state.server_call, g_state.ops,
-                                   (size_t)(op - g_state.ops), tag(2), NULL));
+                                   (size_t)(op - g_state.ops), tag(2), nullptr));
   cleanup_test();
 }
 
@@ -549,18 +549,18 @@ static void test_recv_close_on_server_twice() {
 
   op = g_state.ops;
   op->op = GRPC_OP_RECV_CLOSE_ON_SERVER;
-  op->data.recv_close_on_server.cancelled = NULL;
+  op->data.recv_close_on_server.cancelled = nullptr;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_CLOSE_ON_SERVER;
-  op->data.recv_close_on_server.cancelled = NULL;
+  op->data.recv_close_on_server.cancelled = nullptr;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   GPR_ASSERT(GRPC_CALL_ERROR_TOO_MANY_OPERATIONS ==
              grpc_call_start_batch(g_state.server_call, g_state.ops,
-                                   (size_t)(op - g_state.ops), tag(2), NULL));
+                                   (size_t)(op - g_state.ops), tag(2), nullptr));
   cleanup_test();
 }
 
@@ -578,11 +578,11 @@ static void test_invalid_initial_metadata_reserved_key() {
   op->data.send_initial_metadata.count = 1;
   op->data.send_initial_metadata.metadata = &metadata;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   GPR_ASSERT(GRPC_CALL_ERROR_INVALID_METADATA ==
              grpc_call_start_batch(g_state.call, g_state.ops,
-                                   (size_t)(op - g_state.ops), tag(1), NULL));
+                                   (size_t)(op - g_state.ops), tag(1), nullptr));
   cleanup_test();
 }
 
diff --git a/test/core/end2end/multiple_server_queues_test.cc b/test/core/end2end/multiple_server_queues_test.cc
index 8036ca54b2..dfa3b48b52 100644
--- a/test/core/end2end/multiple_server_queues_test.cc
+++ b/test/core/end2end/multiple_server_queues_test.cc
@@ -34,33 +34,33 @@ int main(int argc, char** argv) {
   attr.cq_completion_type = GRPC_CQ_NEXT;
   attr.cq_polling_type = GRPC_CQ_DEFAULT_POLLING;
   cq1 = grpc_completion_queue_create(
-      grpc_completion_queue_factory_lookup(&attr), &attr, NULL);
+      grpc_completion_queue_factory_lookup(&attr), &attr, nullptr);
 
   attr.cq_polling_type = GRPC_CQ_NON_LISTENING;
   cq2 = grpc_completion_queue_create(
-      grpc_completion_queue_factory_lookup(&attr), &attr, NULL);
+      grpc_completion_queue_factory_lookup(&attr), &attr, nullptr);
 
   attr.cq_polling_type = GRPC_CQ_NON_POLLING;
   cq3 = grpc_completion_queue_create(
-      grpc_completion_queue_factory_lookup(&attr), &attr, NULL);
+      grpc_completion_queue_factory_lookup(&attr), &attr, nullptr);
 
-  server = grpc_server_create(NULL, NULL);
-  grpc_server_register_completion_queue(server, cq1, NULL);
+  server = grpc_server_create(nullptr, nullptr);
+  grpc_server_register_completion_queue(server, cq1, nullptr);
   grpc_server_add_insecure_http2_port(server, "[::]:0");
-  grpc_server_register_completion_queue(server, cq2, NULL);
-  grpc_server_register_completion_queue(server, cq3, NULL);
+  grpc_server_register_completion_queue(server, cq2, nullptr);
+  grpc_server_register_completion_queue(server, cq3, nullptr);
 
   grpc_server_start(server);
-  grpc_server_shutdown_and_notify(server, cq2, NULL);
+  grpc_server_shutdown_and_notify(server, cq2, nullptr);
   grpc_completion_queue_next(cq2, gpr_inf_future(GPR_CLOCK_REALTIME),
-                             NULL); /* cue queue hang */
+                             nullptr); /* cue queue hang */
   grpc_completion_queue_shutdown(cq1);
   grpc_completion_queue_shutdown(cq2);
   grpc_completion_queue_shutdown(cq3);
 
-  grpc_completion_queue_next(cq1, gpr_inf_future(GPR_CLOCK_REALTIME), NULL);
-  grpc_completion_queue_next(cq2, gpr_inf_future(GPR_CLOCK_REALTIME), NULL);
-  grpc_completion_queue_next(cq3, gpr_inf_future(GPR_CLOCK_REALTIME), NULL);
+  grpc_completion_queue_next(cq1, gpr_inf_future(GPR_CLOCK_REALTIME), nullptr);
+  grpc_completion_queue_next(cq2, gpr_inf_future(GPR_CLOCK_REALTIME), nullptr);
+  grpc_completion_queue_next(cq3, gpr_inf_future(GPR_CLOCK_REALTIME), nullptr);
 
   grpc_server_destroy(server);
   grpc_completion_queue_destroy(cq1);
diff --git a/test/core/end2end/no_server_test.cc b/test/core/end2end/no_server_test.cc
index a69b7bc8d6..a35ec575fd 100644
--- a/test/core/end2end/no_server_test.cc
+++ b/test/core/end2end/no_server_test.cc
@@ -44,32 +44,32 @@ int main(int argc, char** argv) {
 
   grpc_metadata_array_init(&trailing_metadata_recv);
 
-  cq = grpc_completion_queue_create_for_next(NULL);
+  cq = grpc_completion_queue_create_for_next(nullptr);
   cqv = cq_verifier_create(cq);
 
   /* create a call, channel to a non existant server */
-  chan = grpc_insecure_channel_create("nonexistant:54321", NULL, NULL);
+  chan = grpc_insecure_channel_create("nonexistant:54321", nullptr, nullptr);
   grpc_slice host = grpc_slice_from_static_string("nonexistant");
-  call = grpc_channel_create_call(chan, NULL, GRPC_PROPAGATE_DEFAULTS, cq,
+  call = grpc_channel_create_call(chan, nullptr, GRPC_PROPAGATE_DEFAULTS, cq,
                                   grpc_slice_from_static_string("/Foo"), &host,
-                                  deadline, NULL);
+                                  deadline, nullptr);
 
   memset(ops, 0, sizeof(ops));
   op = ops;
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
   op->data.send_initial_metadata.count = 0;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_STATUS_ON_CLIENT;
   op->data.recv_status_on_client.trailing_metadata = &trailing_metadata_recv;
   op->data.recv_status_on_client.status = &status;
   op->data.recv_status_on_client.status_details = &details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   GPR_ASSERT(GRPC_CALL_OK == grpc_call_start_batch(
-                                 call, ops, (size_t)(op - ops), tag(1), NULL));
+                                 call, ops, (size_t)(op - ops), tag(1), nullptr));
   /* verify that all tags get completed */
   CQ_EXPECT_COMPLETION(cqv, tag(1), 1);
   cq_verify(cqv);
@@ -78,7 +78,7 @@ int main(int argc, char** argv) {
 
   grpc_completion_queue_shutdown(cq);
   while (
-      grpc_completion_queue_next(cq, gpr_inf_future(GPR_CLOCK_REALTIME), NULL)
+      grpc_completion_queue_next(cq, gpr_inf_future(GPR_CLOCK_REALTIME), nullptr)
           .type != GRPC_QUEUE_SHUTDOWN)
     ;
   grpc_completion_queue_destroy(cq);
diff --git a/test/core/end2end/tests/authority_not_supported.cc b/test/core/end2end/tests/authority_not_supported.cc
index 62fb02ab56..9c8545058c 100644
--- a/test/core/end2end/tests/authority_not_supported.cc
+++ b/test/core/end2end/tests/authority_not_supported.cc
@@ -53,7 +53,7 @@ static gpr_timespec five_seconds_from_now(void) {
 static void drain_cq(grpc_completion_queue* cq) {
   grpc_event ev;
   do {
-    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), NULL);
+    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), nullptr);
   } while (ev.type != GRPC_QUEUE_SHUTDOWN);
 }
 
@@ -62,16 +62,16 @@ static void shutdown_server(grpc_end2end_test_fixture* f) {
   grpc_server_shutdown_and_notify(f->server, f->shutdown_cq, tag(1000));
   GPR_ASSERT(grpc_completion_queue_pluck(f->shutdown_cq, tag(1000),
                                          grpc_timeout_seconds_to_deadline(5),
-                                         NULL)
+                                         nullptr)
                  .type == GRPC_OP_COMPLETE);
   grpc_server_destroy(f->server);
-  f->server = NULL;
+  f->server = nullptr;
 }
 
 static void shutdown_client(grpc_end2end_test_fixture* f) {
   if (!f->client) return;
   grpc_channel_destroy(f->client);
-  f->client = NULL;
+  f->client = nullptr;
 }
 
 static void end_test(grpc_end2end_test_fixture* f) {
@@ -94,28 +94,28 @@ static void test_with_authority_header(grpc_end2end_test_config config) {
   grpc_metadata meta_c[2] = {{grpc_slice_from_static_string("key1"),
                               grpc_slice_from_static_string("val1"),
                               0,
-                              {{NULL, NULL, NULL, NULL}}},
+                              {{nullptr, nullptr, nullptr, nullptr}}},
                              {grpc_slice_from_static_string("key2"),
                               grpc_slice_from_static_string("val2"),
                               0,
-                              {{NULL, NULL, NULL, NULL}}}};
+                              {{nullptr, nullptr, nullptr, nullptr}}}};
   grpc_end2end_test_fixture f =
-      begin_test(config, "test_with_authority_header", NULL, NULL);
+      begin_test(config, "test_with_authority_header", nullptr, nullptr);
   cq_verifier* cqv = cq_verifier_create(f.cq);
   grpc_op ops[6];
   grpc_op* op;
   grpc_metadata_array initial_metadata_recv;
   grpc_metadata_array trailing_metadata_recv;
-  grpc_byte_buffer* response_payload_recv = NULL;
+  grpc_byte_buffer* response_payload_recv = nullptr;
   grpc_status_code status;
   grpc_call_error error;
   grpc_slice details;
 
   grpc_slice host = grpc_slice_from_static_string("foo.test.google.fr");
   gpr_timespec deadline = five_seconds_from_now();
-  c = grpc_channel_create_call(f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+  c = grpc_channel_create_call(f.client, nullptr, GRPC_PROPAGATE_DEFAULTS, f.cq,
                                grpc_slice_from_static_string("/foo"), &host,
-                               deadline, NULL);
+                               deadline, nullptr);
   GPR_ASSERT(c);
 
   grpc_metadata_array_init(&initial_metadata_recv);
@@ -127,35 +127,35 @@ static void test_with_authority_header(grpc_end2end_test_config config) {
   op->data.send_initial_metadata.count = 2;
   op->data.send_initial_metadata.metadata = meta_c;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_MESSAGE;
   op->data.send_message.send_message = request_payload;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_CLOSE_FROM_CLIENT;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_INITIAL_METADATA;
   op->data.recv_initial_metadata.recv_initial_metadata = &initial_metadata_recv;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_MESSAGE;
   op->data.recv_message.recv_message = &response_payload_recv;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_STATUS_ON_CLIENT;
   op->data.recv_status_on_client.trailing_metadata = &trailing_metadata_recv;
   op->data.recv_status_on_client.status = &status;
   op->data.recv_status_on_client.status_details = &details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), NULL);
+  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   CQ_EXPECT_COMPLETION(cqv, tag(1), 1);
diff --git a/test/core/end2end/tests/bad_hostname.cc b/test/core/end2end/tests/bad_hostname.cc
index c54cb8ed34..97ef62b5e3 100644
--- a/test/core/end2end/tests/bad_hostname.cc
+++ b/test/core/end2end/tests/bad_hostname.cc
@@ -55,7 +55,7 @@ static gpr_timespec five_seconds_from_now(void) {
 static void drain_cq(grpc_completion_queue* cq) {
   grpc_event ev;
   do {
-    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), NULL);
+    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), nullptr);
   } while (ev.type != GRPC_QUEUE_SHUTDOWN);
 }
 
@@ -64,16 +64,16 @@ static void shutdown_server(grpc_end2end_test_fixture* f) {
   grpc_server_shutdown_and_notify(f->server, f->shutdown_cq, tag(1000));
   GPR_ASSERT(grpc_completion_queue_pluck(f->shutdown_cq, tag(1000),
                                          grpc_timeout_seconds_to_deadline(5),
-                                         NULL)
+                                         nullptr)
                  .type == GRPC_OP_COMPLETE);
   grpc_server_destroy(f->server);
-  f->server = NULL;
+  f->server = nullptr;
 }
 
 static void shutdown_client(grpc_end2end_test_fixture* f) {
   if (!f->client) return;
   grpc_channel_destroy(f->client);
-  f->client = NULL;
+  f->client = nullptr;
 }
 
 static void end_test(grpc_end2end_test_fixture* f) {
@@ -101,9 +101,9 @@ static void simple_request_body(grpc_end2end_test_fixture f) {
 
   grpc_slice host = grpc_slice_from_static_string("slartibartfast.local");
   gpr_timespec deadline = five_seconds_from_now();
-  c = grpc_channel_create_call(f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+  c = grpc_channel_create_call(f.client, nullptr, GRPC_PROPAGATE_DEFAULTS, f.cq,
                                grpc_slice_from_static_string("/foo"), &host,
-                               deadline, NULL);
+                               deadline, nullptr);
   GPR_ASSERT(c);
 
   grpc_metadata_array_init(&initial_metadata_recv);
@@ -116,25 +116,25 @@ static void simple_request_body(grpc_end2end_test_fixture f) {
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
   op->data.send_initial_metadata.count = 0;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_CLOSE_FROM_CLIENT;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_INITIAL_METADATA;
   op->data.recv_initial_metadata.recv_initial_metadata = &initial_metadata_recv;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_STATUS_ON_CLIENT;
   op->data.recv_status_on_client.trailing_metadata = &trailing_metadata_recv;
   op->data.recv_status_on_client.status = &status;
   op->data.recv_status_on_client.status_details = &details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), NULL);
+  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   CQ_EXPECT_COMPLETION(cqv, tag(1), 1);
@@ -156,7 +156,7 @@ static void simple_request_body(grpc_end2end_test_fixture f) {
 static void test_invoke_simple_request(grpc_end2end_test_config config) {
   grpc_end2end_test_fixture f;
 
-  f = begin_test(config, "test_invoke_simple_request", NULL, NULL);
+  f = begin_test(config, "test_invoke_simple_request", nullptr, nullptr);
   simple_request_body(f);
   end_test(&f);
   config.tear_down_data(&f);
diff --git a/test/core/end2end/tests/bad_ping.cc b/test/core/end2end/tests/bad_ping.cc
index 648061587c..30a1b8de77 100644
--- a/test/core/end2end/tests/bad_ping.cc
+++ b/test/core/end2end/tests/bad_ping.cc
@@ -37,20 +37,20 @@ static void drain_cq(grpc_completion_queue* cq) {
   grpc_event ev;
   do {
     ev = grpc_completion_queue_next(cq, grpc_timeout_seconds_to_deadline(5),
-                                    NULL);
+                                    nullptr);
   } while (ev.type != GRPC_QUEUE_SHUTDOWN);
 }
 
 static void shutdown_server(grpc_end2end_test_fixture* f) {
   if (!f->server) return;
   grpc_server_destroy(f->server);
-  f->server = NULL;
+  f->server = nullptr;
 }
 
 static void shutdown_client(grpc_end2end_test_fixture* f) {
   if (!f->client) return;
   grpc_channel_destroy(f->client);
-  f->client = NULL;
+  f->client = nullptr;
 }
 
 static void end_test(grpc_end2end_test_fixture* f) {
@@ -64,7 +64,7 @@ static void end_test(grpc_end2end_test_fixture* f) {
 }
 
 static void test_bad_ping(grpc_end2end_test_config config) {
-  grpc_end2end_test_fixture f = config.create_fixture(NULL, NULL);
+  grpc_end2end_test_fixture f = config.create_fixture(nullptr, nullptr);
   cq_verifier* cqv = cq_verifier_create(f.cq);
   grpc_arg client_a[3];
   client_a[0].type = GRPC_ARG_INTEGER;
@@ -109,10 +109,10 @@ static void test_bad_ping(grpc_end2end_test_config config) {
   int was_cancelled = 2;
 
   c = grpc_channel_create_call(
-      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+      f.client, nullptr, GRPC_PROPAGATE_DEFAULTS, f.cq,
       grpc_slice_from_static_string("/foo"),
       get_host_override_slice("foo.test.google.fr:1234", config), deadline,
-      NULL);
+      nullptr);
   GPR_ASSERT(c);
 
   grpc_metadata_array_init(&initial_metadata_recv);
@@ -124,27 +124,27 @@ static void test_bad_ping(grpc_end2end_test_config config) {
   op = ops;
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
   op->data.send_initial_metadata.count = 0;
-  op->data.send_initial_metadata.metadata = NULL;
+  op->data.send_initial_metadata.metadata = nullptr;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_CLOSE_FROM_CLIENT;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_INITIAL_METADATA;
   op->data.recv_initial_metadata.recv_initial_metadata = &initial_metadata_recv;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_STATUS_ON_CLIENT;
   op->data.recv_status_on_client.trailing_metadata = &trailing_metadata_recv;
   op->data.recv_status_on_client.status = &status;
   op->data.recv_status_on_client.status_details = &details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), NULL);
+  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   error =
@@ -160,7 +160,7 @@ static void test_bad_ping(grpc_end2end_test_config config) {
   // needed here.
   int i;
   for (i = 1; i <= MAX_PING_STRIKES + 1; i++) {
-    grpc_channel_ping(f.client, f.cq, tag(200 + i), NULL);
+    grpc_channel_ping(f.client, f.cq, tag(200 + i), nullptr);
     CQ_EXPECT_COMPLETION(cqv, tag(200 + i), 1);
     if (i == MAX_PING_STRIKES + 1) {
       CQ_EXPECT_COMPLETION(cqv, tag(1), 1);
@@ -173,7 +173,7 @@ static void test_bad_ping(grpc_end2end_test_config config) {
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
   op->data.send_initial_metadata.count = 0;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_STATUS_FROM_SERVER;
   op->data.send_status_from_server.trailing_metadata_count = 0;
@@ -181,14 +181,14 @@ static void test_bad_ping(grpc_end2end_test_config config) {
   grpc_slice status_details = grpc_slice_from_static_string("xyz");
   op->data.send_status_from_server.status_details = &status_details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_CLOSE_ON_SERVER;
   op->data.recv_close_on_server.cancelled = &was_cancelled;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(102), NULL);
+  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(102), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   CQ_EXPECT_COMPLETION(cqv, tag(102), 1);
diff --git a/test/core/end2end/tests/binary_metadata.cc b/test/core/end2end/tests/binary_metadata.cc
index 52f0c70862..b22bd35711 100644
--- a/test/core/end2end/tests/binary_metadata.cc
+++ b/test/core/end2end/tests/binary_metadata.cc
@@ -53,7 +53,7 @@ static gpr_timespec five_seconds_from_now(void) {
 static void drain_cq(grpc_completion_queue* cq) {
   grpc_event ev;
   do {
-    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), NULL);
+    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), nullptr);
   } while (ev.type != GRPC_QUEUE_SHUTDOWN);
 }
 
@@ -62,16 +62,16 @@ static void shutdown_server(grpc_end2end_test_fixture* f) {
   grpc_server_shutdown_and_notify(f->server, f->shutdown_cq, tag(1000));
   GPR_ASSERT(grpc_completion_queue_pluck(f->shutdown_cq, tag(1000),
                                          grpc_timeout_seconds_to_deadline(5),
-                                         NULL)
+                                         nullptr)
                  .type == GRPC_OP_COMPLETE);
   grpc_server_destroy(f->server);
-  f->server = NULL;
+  f->server = nullptr;
 }
 
 static void shutdown_client(grpc_end2end_test_fixture* f) {
   if (!f->client) return;
   grpc_channel_destroy(f->client);
-  f->client = NULL;
+  f->client = nullptr;
 }
 
 static void end_test(grpc_end2end_test_fixture* f) {
@@ -102,33 +102,33 @@ static void test_request_response_with_metadata_and_payload(
        grpc_slice_from_static_string(
            "\xc0\xc1\xc2\xc3\xc4\xc5\xc6\xc7\xc8\xc9\xca\xcb\xcc"),
        0,
-       {{NULL, NULL, NULL, NULL}}},
+       {{nullptr, nullptr, nullptr, nullptr}}},
       {grpc_slice_from_static_string("key2-bin"),
        grpc_slice_from_static_string(
            "\x10\x11\x12\x13\x14\x15\x16\x17\x18\x19\x1a\x1b\x1c\x1d"),
        0,
-       {{NULL, NULL, NULL, NULL}}}};
+       {{nullptr, nullptr, nullptr, nullptr}}}};
   grpc_metadata meta_s[2] = {
       {grpc_slice_from_static_string("key3-bin"),
        grpc_slice_from_static_string(
            "\xe0\xe1\xe2\xe3\xe4\xe5\xe6\xe7\xe8\xe9\xea\xeb\xec\xed\xee"),
        0,
-       {{NULL, NULL, NULL, NULL}}},
+       {{nullptr, nullptr, nullptr, nullptr}}},
       {grpc_slice_from_static_string("key4-bin"),
        grpc_slice_from_static_string(
            "\xf0\xf1\xf2\xf3\xf4\xf5\xf6\xf7\xf8\xf9\xfa\xfb\xfc\xfd\xfe\xff"),
        0,
-       {{NULL, NULL, NULL, NULL}}}};
+       {{nullptr, nullptr, nullptr, nullptr}}}};
   grpc_end2end_test_fixture f = begin_test(
-      config, "test_request_response_with_metadata_and_payload", NULL, NULL);
+      config, "test_request_response_with_metadata_and_payload", nullptr, nullptr);
   cq_verifier* cqv = cq_verifier_create(f.cq);
   grpc_op ops[6];
   grpc_op* op;
   grpc_metadata_array initial_metadata_recv;
   grpc_metadata_array trailing_metadata_recv;
   grpc_metadata_array request_metadata_recv;
-  grpc_byte_buffer* request_payload_recv = NULL;
-  grpc_byte_buffer* response_payload_recv = NULL;
+  grpc_byte_buffer* request_payload_recv = nullptr;
+  grpc_byte_buffer* response_payload_recv = nullptr;
   grpc_call_details call_details;
   grpc_status_code status;
   grpc_call_error error;
@@ -137,10 +137,10 @@ static void test_request_response_with_metadata_and_payload(
 
   gpr_timespec deadline = five_seconds_from_now();
   c = grpc_channel_create_call(
-      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+      f.client, nullptr, GRPC_PROPAGATE_DEFAULTS, f.cq,
       grpc_slice_from_static_string("/foo"),
       get_host_override_slice("foo.test.google.fr:1234", config), deadline,
-      NULL);
+      nullptr);
   GPR_ASSERT(c);
 
   grpc_metadata_array_init(&initial_metadata_recv);
@@ -154,35 +154,35 @@ static void test_request_response_with_metadata_and_payload(
   op->data.send_initial_metadata.count = 2;
   op->data.send_initial_metadata.metadata = meta_c;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_MESSAGE;
   op->data.send_message.send_message = request_payload;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_CLOSE_FROM_CLIENT;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_INITIAL_METADATA;
   op->data.recv_initial_metadata.recv_initial_metadata = &initial_metadata_recv;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_MESSAGE;
   op->data.recv_message.recv_message = &response_payload_recv;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_STATUS_ON_CLIENT;
   op->data.recv_status_on_client.trailing_metadata = &trailing_metadata_recv;
   op->data.recv_status_on_client.status = &status;
   op->data.recv_status_on_client.status_details = &details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), NULL);
+  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   error =
@@ -198,14 +198,14 @@ static void test_request_response_with_metadata_and_payload(
   op->data.send_initial_metadata.count = 2;
   op->data.send_initial_metadata.metadata = meta_s;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_MESSAGE;
   op->data.recv_message.recv_message = &request_payload_recv;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(102), NULL);
+  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(102), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   CQ_EXPECT_COMPLETION(cqv, tag(102), 1);
@@ -216,12 +216,12 @@ static void test_request_response_with_metadata_and_payload(
   op->op = GRPC_OP_RECV_CLOSE_ON_SERVER;
   op->data.recv_close_on_server.cancelled = &was_cancelled;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_MESSAGE;
   op->data.send_message.send_message = response_payload;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_STATUS_FROM_SERVER;
   op->data.send_status_from_server.trailing_metadata_count = 0;
@@ -244,9 +244,9 @@ static void test_request_response_with_metadata_and_payload(
       "\xfd\xfe\xff");
   op->data.send_status_from_server.status_details = &status_string;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(103), NULL);
+  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(103), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   CQ_EXPECT_COMPLETION(cqv, tag(103), 1);
diff --git a/test/core/end2end/tests/call_creds.cc b/test/core/end2end/tests/call_creds.cc
index fc550b7733..fb9d8554ce 100644
--- a/test/core/end2end/tests/call_creds.cc
+++ b/test/core/end2end/tests/call_creds.cc
@@ -45,19 +45,19 @@ static grpc_end2end_test_fixture begin_test(grpc_end2end_test_config config,
                                             int fail_server_auth_check) {
   grpc_end2end_test_fixture f;
   gpr_log(GPR_INFO, "Running test: %s/%s", test_name, config.name);
-  f = config.create_fixture(NULL, NULL);
-  config.init_client(&f, NULL);
+  f = config.create_fixture(nullptr, nullptr);
+  config.init_client(&f, nullptr);
   if (fail_server_auth_check) {
     grpc_arg fail_auth_arg = {
         GRPC_ARG_STRING,
         const_cast<char*>(FAIL_AUTH_CHECK_SERVER_ARG_NAME),
-        {NULL}};
+        {nullptr}};
     grpc_channel_args args;
     args.num_args = 1;
     args.args = &fail_auth_arg;
     config.init_server(&f, &args);
   } else {
-    config.init_server(&f, NULL);
+    config.init_server(&f, nullptr);
   }
   return f;
 }
@@ -73,7 +73,7 @@ static gpr_timespec five_seconds_from_now(void) {
 static void drain_cq(grpc_completion_queue* cq) {
   grpc_event ev;
   do {
-    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), NULL);
+    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), nullptr);
   } while (ev.type != GRPC_QUEUE_SHUTDOWN);
 }
 
@@ -82,16 +82,16 @@ static void shutdown_server(grpc_end2end_test_fixture* f) {
   grpc_server_shutdown_and_notify(f->server, f->shutdown_cq, tag(1000));
   GPR_ASSERT(grpc_completion_queue_pluck(f->shutdown_cq, tag(1000),
                                          grpc_timeout_seconds_to_deadline(5),
-                                         NULL)
+                                         nullptr)
                  .type == GRPC_OP_COMPLETE);
   grpc_server_destroy(f->server);
-  f->server = NULL;
+  f->server = nullptr;
 }
 
 static void shutdown_client(grpc_end2end_test_fixture* f) {
   if (!f->client) return;
   grpc_channel_destroy(f->client);
-  f->client = NULL;
+  f->client = nullptr;
 }
 
 static void end_test(grpc_end2end_test_fixture* f) {
@@ -111,12 +111,12 @@ static void print_auth_context(int is_client, const grpc_auth_context* ctx) {
   gpr_log(GPR_INFO, "\tauthenticated: %s",
           grpc_auth_context_peer_is_authenticated(ctx) ? "YES" : "NO");
   it = grpc_auth_context_peer_identity(ctx);
-  while ((p = grpc_auth_property_iterator_next(&it)) != NULL) {
+  while ((p = grpc_auth_property_iterator_next(&it)) != nullptr) {
     gpr_log(GPR_INFO, "\t\t%s: %s", p->name, p->value);
   }
   gpr_log(GPR_INFO, "\tall properties:");
   it = grpc_auth_context_property_iterator(ctx);
-  while ((p = grpc_auth_property_iterator_next(&it)) != NULL) {
+  while ((p = grpc_auth_property_iterator_next(&it)) != nullptr) {
     gpr_log(GPR_INFO, "\t\t%s: %s", p->name, p->value);
   }
 }
@@ -141,29 +141,29 @@ static void request_response_with_payload_and_call_creds(
   grpc_metadata_array initial_metadata_recv;
   grpc_metadata_array trailing_metadata_recv;
   grpc_metadata_array request_metadata_recv;
-  grpc_byte_buffer* request_payload_recv = NULL;
-  grpc_byte_buffer* response_payload_recv = NULL;
+  grpc_byte_buffer* request_payload_recv = nullptr;
+  grpc_byte_buffer* response_payload_recv = nullptr;
   grpc_call_details call_details;
   grpc_status_code status;
   grpc_call_error error;
   grpc_slice details;
   int was_cancelled = 2;
-  grpc_call_credentials* creds = NULL;
-  grpc_auth_context* s_auth_context = NULL;
-  grpc_auth_context* c_auth_context = NULL;
+  grpc_call_credentials* creds = nullptr;
+  grpc_auth_context* s_auth_context = nullptr;
+  grpc_auth_context* c_auth_context = nullptr;
 
   f = begin_test(config, test_name, 0);
   cqv = cq_verifier_create(f.cq);
 
   gpr_timespec deadline = five_seconds_from_now();
   c = grpc_channel_create_call(
-      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+      f.client, nullptr, GRPC_PROPAGATE_DEFAULTS, f.cq,
       grpc_slice_from_static_string("/foo"),
       get_host_override_slice("foo.test.google.fr:1234", config), deadline,
-      NULL);
+      nullptr);
   GPR_ASSERT(c);
-  creds = grpc_google_iam_credentials_create(iam_token, iam_selector, NULL);
-  GPR_ASSERT(creds != NULL);
+  creds = grpc_google_iam_credentials_create(iam_token, iam_selector, nullptr);
+  GPR_ASSERT(creds != nullptr);
   GPR_ASSERT(grpc_call_set_credentials(c, creds) == GRPC_CALL_OK);
   switch (mode) {
     case NONE:
@@ -171,12 +171,12 @@ static void request_response_with_payload_and_call_creds(
     case OVERRIDE:
       grpc_call_credentials_release(creds);
       creds = grpc_google_iam_credentials_create(overridden_iam_token,
-                                                 overridden_iam_selector, NULL);
-      GPR_ASSERT(creds != NULL);
+                                                 overridden_iam_selector, nullptr);
+      GPR_ASSERT(creds != nullptr);
       GPR_ASSERT(grpc_call_set_credentials(c, creds) == GRPC_CALL_OK);
       break;
     case DESTROY:
-      GPR_ASSERT(grpc_call_set_credentials(c, NULL) == GRPC_CALL_OK);
+      GPR_ASSERT(grpc_call_set_credentials(c, nullptr) == GRPC_CALL_OK);
       break;
   }
   grpc_call_credentials_release(creds);
@@ -191,35 +191,35 @@ static void request_response_with_payload_and_call_creds(
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
   op->data.send_initial_metadata.count = 0;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_MESSAGE;
   op->data.send_message.send_message = request_payload;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_CLOSE_FROM_CLIENT;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_INITIAL_METADATA;
   op->data.recv_initial_metadata.recv_initial_metadata = &initial_metadata_recv;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_MESSAGE;
   op->data.recv_message.recv_message = &response_payload_recv;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_STATUS_ON_CLIENT;
   op->data.recv_status_on_client.trailing_metadata = &trailing_metadata_recv;
   op->data.recv_status_on_client.status = &status;
   op->data.recv_status_on_client.status_details = &details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), NULL);
+  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   error =
@@ -229,31 +229,31 @@ static void request_response_with_payload_and_call_creds(
   CQ_EXPECT_COMPLETION(cqv, tag(101), 1);
   cq_verify(cqv);
   s_auth_context = grpc_call_auth_context(s);
-  GPR_ASSERT(s_auth_context != NULL);
+  GPR_ASSERT(s_auth_context != nullptr);
   print_auth_context(0, s_auth_context);
   grpc_auth_context_release(s_auth_context);
 
   c_auth_context = grpc_call_auth_context(c);
-  GPR_ASSERT(c_auth_context != NULL);
+  GPR_ASSERT(c_auth_context != nullptr);
   print_auth_context(1, c_auth_context);
   grpc_auth_context_release(c_auth_context);
 
   /* Cannot set creds on the server call object. */
-  GPR_ASSERT(grpc_call_set_credentials(s, NULL) != GRPC_CALL_OK);
+  GPR_ASSERT(grpc_call_set_credentials(s, nullptr) != GRPC_CALL_OK);
 
   memset(ops, 0, sizeof(ops));
   op = ops;
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
   op->data.send_initial_metadata.count = 0;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_MESSAGE;
   op->data.recv_message.recv_message = &request_payload_recv;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(102), NULL);
+  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(102), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   CQ_EXPECT_COMPLETION(cqv, tag(102), 1);
@@ -264,12 +264,12 @@ static void request_response_with_payload_and_call_creds(
   op->op = GRPC_OP_RECV_CLOSE_ON_SERVER;
   op->data.recv_close_on_server.cancelled = &was_cancelled;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_MESSAGE;
   op->data.send_message.send_message = response_payload;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_STATUS_FROM_SERVER;
   op->data.send_status_from_server.trailing_metadata_count = 0;
@@ -277,9 +277,9 @@ static void request_response_with_payload_and_call_creds(
   grpc_slice status_details = grpc_slice_from_static_string("xyz");
   op->data.send_status_from_server.status_details = &status_details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(103), NULL);
+  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(103), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   CQ_EXPECT_COMPLETION(cqv, tag(103), 1);
@@ -383,7 +383,7 @@ static void test_request_with_server_rejecting_client_creds(
   grpc_status_code status;
   grpc_call_error error;
   grpc_slice details;
-  grpc_byte_buffer* response_payload_recv = NULL;
+  grpc_byte_buffer* response_payload_recv = nullptr;
   grpc_slice request_payload_slice =
       grpc_slice_from_copied_string("hello world");
   grpc_byte_buffer* request_payload =
@@ -394,14 +394,14 @@ static void test_request_with_server_rejecting_client_creds(
   cqv = cq_verifier_create(f.cq);
 
   c = grpc_channel_create_call(
-      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+      f.client, nullptr, GRPC_PROPAGATE_DEFAULTS, f.cq,
       grpc_slice_from_static_string("/foo"),
       get_host_override_slice("foo.test.google.fr:1234", config), deadline,
-      NULL);
+      nullptr);
   GPR_ASSERT(c);
 
-  creds = grpc_google_iam_credentials_create(iam_token, iam_selector, NULL);
-  GPR_ASSERT(creds != NULL);
+  creds = grpc_google_iam_credentials_create(iam_token, iam_selector, nullptr);
+  GPR_ASSERT(creds != nullptr);
   GPR_ASSERT(grpc_call_set_credentials(c, creds) == GRPC_CALL_OK);
   grpc_call_credentials_release(creds);
 
@@ -417,33 +417,33 @@ static void test_request_with_server_rejecting_client_creds(
   op->data.recv_status_on_client.status = &status;
   op->data.recv_status_on_client.status_details = &details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
   op->data.send_initial_metadata.count = 0;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_MESSAGE;
   op->data.send_message.send_message = request_payload;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_CLOSE_FROM_CLIENT;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_INITIAL_METADATA;
   op->data.recv_initial_metadata.recv_initial_metadata = &initial_metadata_recv;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_MESSAGE;
   op->data.recv_message.recv_message = &response_payload_recv;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), NULL);
+  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), nullptr);
   GPR_ASSERT(error == GRPC_CALL_OK);
 
   CQ_EXPECT_COMPLETION(cqv, tag(1), 1);
diff --git a/test/core/end2end/tests/cancel_after_accept.cc b/test/core/end2end/tests/cancel_after_accept.cc
index e2ad5bd721..83439d71d2 100644
--- a/test/core/end2end/tests/cancel_after_accept.cc
+++ b/test/core/end2end/tests/cancel_after_accept.cc
@@ -63,7 +63,7 @@ static gpr_timespec five_seconds_from_now(void) {
 static void drain_cq(grpc_completion_queue* cq) {
   grpc_event ev;
   do {
-    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), NULL);
+    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), nullptr);
   } while (ev.type != GRPC_QUEUE_SHUTDOWN);
 }
 
@@ -72,16 +72,16 @@ static void shutdown_server(grpc_end2end_test_fixture* f) {
   grpc_server_shutdown_and_notify(f->server, f->shutdown_cq, tag(1000));
   GPR_ASSERT(grpc_completion_queue_pluck(f->shutdown_cq, tag(1000),
                                          grpc_timeout_seconds_to_deadline(5),
-                                         NULL)
+                                         nullptr)
                  .type == GRPC_OP_COMPLETE);
   grpc_server_destroy(f->server);
-  f->server = NULL;
+  f->server = nullptr;
 }
 
 static void shutdown_client(grpc_end2end_test_fixture* f) {
   if (!f->client) return;
   grpc_channel_destroy(f->client);
-  f->client = NULL;
+  f->client = nullptr;
 }
 
 static void end_test(grpc_end2end_test_fixture* f) {
@@ -109,8 +109,8 @@ static void test_cancel_after_accept(grpc_end2end_test_config config,
   grpc_status_code status;
   grpc_call_error error;
   grpc_slice details;
-  grpc_byte_buffer* request_payload_recv = NULL;
-  grpc_byte_buffer* response_payload_recv = NULL;
+  grpc_byte_buffer* request_payload_recv = nullptr;
+  grpc_byte_buffer* response_payload_recv = nullptr;
   grpc_slice request_payload_slice =
       grpc_slice_from_copied_string("hello world");
   grpc_slice response_payload_slice =
@@ -121,7 +121,7 @@ static void test_cancel_after_accept(grpc_end2end_test_config config,
       grpc_raw_byte_buffer_create(&response_payload_slice, 1);
   int was_cancelled = 2;
 
-  grpc_channel_args* args = NULL;
+  grpc_channel_args* args = nullptr;
   if (use_service_config) {
     grpc_arg arg;
     arg.type = GRPC_ARG_STRING;
@@ -140,17 +140,17 @@ static void test_cancel_after_accept(grpc_end2end_test_config config,
   }
 
   grpc_end2end_test_fixture f = begin_test(config, "cancel_after_accept", mode,
-                                           use_service_config, args, NULL);
+                                           use_service_config, args, nullptr);
   cq_verifier* cqv = cq_verifier_create(f.cq);
 
   gpr_timespec deadline = use_service_config
                               ? gpr_inf_future(GPR_CLOCK_MONOTONIC)
                               : five_seconds_from_now();
   c = grpc_channel_create_call(
-      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+      f.client, nullptr, GRPC_PROPAGATE_DEFAULTS, f.cq,
       grpc_slice_from_static_string("/service/method"),
       get_host_override_slice("foo.test.google.fr:1234", config), deadline,
-      NULL);
+      nullptr);
   GPR_ASSERT(c);
 
   grpc_metadata_array_init(&initial_metadata_recv);
@@ -165,29 +165,29 @@ static void test_cancel_after_accept(grpc_end2end_test_config config,
   op->data.recv_status_on_client.status = &status;
   op->data.recv_status_on_client.status_details = &details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
   op->data.send_initial_metadata.count = 0;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_MESSAGE;
   op->data.send_message.send_message = request_payload;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_INITIAL_METADATA;
   op->data.recv_initial_metadata.recv_initial_metadata = &initial_metadata_recv;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_MESSAGE;
   op->data.recv_message.recv_message = &response_payload_recv;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), NULL);
+  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   error = grpc_server_request_call(f.server, &s, &call_details,
@@ -201,27 +201,27 @@ static void test_cancel_after_accept(grpc_end2end_test_config config,
   op->op = GRPC_OP_RECV_MESSAGE;
   op->data.recv_message.recv_message = &request_payload_recv;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
   op->data.send_initial_metadata.count = 0;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_MESSAGE;
   op->data.send_message.send_message = response_payload;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_CLOSE_ON_SERVER;
   op->data.recv_close_on_server.cancelled = &was_cancelled;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(3), NULL);
+  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(3), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
-  GPR_ASSERT(GRPC_CALL_OK == mode.initiate_cancel(c, NULL));
+  GPR_ASSERT(GRPC_CALL_OK == mode.initiate_cancel(c, nullptr));
 
   CQ_EXPECT_COMPLETION(cqv, tag(3), 1);
   CQ_EXPECT_COMPLETION(cqv, tag(1), 1);
@@ -244,7 +244,7 @@ static void test_cancel_after_accept(grpc_end2end_test_config config,
   grpc_call_unref(c);
   grpc_call_unref(s);
 
-  if (args != NULL) {
+  if (args != nullptr) {
     grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
     grpc_channel_args_destroy(&exec_ctx, args);
     grpc_exec_ctx_finish(&exec_ctx);
diff --git a/test/core/end2end/tests/cancel_after_client_done.cc b/test/core/end2end/tests/cancel_after_client_done.cc
index 90db7f51b2..28379a2f6e 100644
--- a/test/core/end2end/tests/cancel_after_client_done.cc
+++ b/test/core/end2end/tests/cancel_after_client_done.cc
@@ -56,7 +56,7 @@ static gpr_timespec five_seconds_from_now(void) {
 static void drain_cq(grpc_completion_queue* cq) {
   grpc_event ev;
   do {
-    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), NULL);
+    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), nullptr);
   } while (ev.type != GRPC_QUEUE_SHUTDOWN);
 }
 
@@ -65,16 +65,16 @@ static void shutdown_server(grpc_end2end_test_fixture* f) {
   grpc_server_shutdown_and_notify(f->server, f->shutdown_cq, tag(1000));
   GPR_ASSERT(grpc_completion_queue_pluck(f->shutdown_cq, tag(1000),
                                          grpc_timeout_seconds_to_deadline(5),
-                                         NULL)
+                                         nullptr)
                  .type == GRPC_OP_COMPLETE);
   grpc_server_destroy(f->server);
-  f->server = NULL;
+  f->server = nullptr;
 }
 
 static void shutdown_client(grpc_end2end_test_fixture* f) {
   if (!f->client) return;
   grpc_channel_destroy(f->client);
-  f->client = NULL;
+  f->client = nullptr;
 }
 
 static void end_test(grpc_end2end_test_fixture* f) {
@@ -95,7 +95,7 @@ static void test_cancel_after_accept_and_writes_closed(
   grpc_call* c;
   grpc_call* s;
   grpc_end2end_test_fixture f = begin_test(
-      config, "test_cancel_after_accept_and_writes_closed", mode, NULL, NULL);
+      config, "test_cancel_after_accept_and_writes_closed", mode, nullptr, nullptr);
   cq_verifier* cqv = cq_verifier_create(f.cq);
   grpc_metadata_array initial_metadata_recv;
   grpc_metadata_array trailing_metadata_recv;
@@ -104,8 +104,8 @@ static void test_cancel_after_accept_and_writes_closed(
   grpc_status_code status;
   grpc_call_error error;
   grpc_slice details;
-  grpc_byte_buffer* request_payload_recv = NULL;
-  grpc_byte_buffer* response_payload_recv = NULL;
+  grpc_byte_buffer* request_payload_recv = nullptr;
+  grpc_byte_buffer* response_payload_recv = nullptr;
   grpc_slice request_payload_slice =
       grpc_slice_from_copied_string("hello world");
   grpc_slice response_payload_slice =
@@ -118,10 +118,10 @@ static void test_cancel_after_accept_and_writes_closed(
 
   gpr_timespec deadline = five_seconds_from_now();
   c = grpc_channel_create_call(
-      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+      f.client, nullptr, GRPC_PROPAGATE_DEFAULTS, f.cq,
       grpc_slice_from_static_string("/foo"),
       get_host_override_slice("foo.test.google.fr:1234", config), deadline,
-      NULL);
+      nullptr);
   GPR_ASSERT(c);
 
   grpc_metadata_array_init(&initial_metadata_recv);
@@ -136,33 +136,33 @@ static void test_cancel_after_accept_and_writes_closed(
   op->data.recv_status_on_client.status = &status;
   op->data.recv_status_on_client.status_details = &details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
   op->data.send_initial_metadata.count = 0;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_MESSAGE;
   op->data.send_message.send_message = request_payload;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_CLOSE_FROM_CLIENT;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_INITIAL_METADATA;
   op->data.recv_initial_metadata.recv_initial_metadata = &initial_metadata_recv;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_MESSAGE;
   op->data.recv_message.recv_message = &response_payload_recv;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), NULL);
+  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   error = grpc_server_request_call(f.server, &s, &call_details,
@@ -176,27 +176,27 @@ static void test_cancel_after_accept_and_writes_closed(
   op->op = GRPC_OP_RECV_MESSAGE;
   op->data.recv_message.recv_message = &request_payload_recv;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_CLOSE_ON_SERVER;
   op->data.recv_close_on_server.cancelled = &was_cancelled;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
   op->data.send_initial_metadata.count = 0;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_MESSAGE;
   op->data.send_message.send_message = response_payload;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(3), NULL);
+  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(3), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
-  GPR_ASSERT(GRPC_CALL_OK == mode.initiate_cancel(c, NULL));
+  GPR_ASSERT(GRPC_CALL_OK == mode.initiate_cancel(c, nullptr));
 
   CQ_EXPECT_COMPLETION(cqv, tag(3), 1);
   CQ_EXPECT_COMPLETION(cqv, tag(1), 1);
diff --git a/test/core/end2end/tests/cancel_after_invoke.cc b/test/core/end2end/tests/cancel_after_invoke.cc
index 7f0c4e7af9..d3891b160e 100644
--- a/test/core/end2end/tests/cancel_after_invoke.cc
+++ b/test/core/end2end/tests/cancel_after_invoke.cc
@@ -57,7 +57,7 @@ static gpr_timespec five_seconds_from_now(void) {
 static void drain_cq(grpc_completion_queue* cq) {
   grpc_event ev;
   do {
-    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), NULL);
+    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), nullptr);
   } while (ev.type != GRPC_QUEUE_SHUTDOWN);
 }
 
@@ -65,17 +65,17 @@ static void shutdown_server(grpc_end2end_test_fixture* f) {
   if (!f->server) return;
   grpc_server_shutdown_and_notify(f->server, f->cq, tag(1000));
   grpc_event ev = grpc_completion_queue_next(
-      f->cq, grpc_timeout_seconds_to_deadline(5), NULL);
+      f->cq, grpc_timeout_seconds_to_deadline(5), nullptr);
   GPR_ASSERT(ev.type == GRPC_OP_COMPLETE);
   GPR_ASSERT(ev.tag == tag(1000));
   grpc_server_destroy(f->server);
-  f->server = NULL;
+  f->server = nullptr;
 }
 
 static void shutdown_client(grpc_end2end_test_fixture* f) {
   if (!f->client) return;
   grpc_channel_destroy(f->client);
-  f->client = NULL;
+  f->client = nullptr;
 }
 
 static void end_test(grpc_end2end_test_fixture* f) {
@@ -95,7 +95,7 @@ static void test_cancel_after_invoke(grpc_end2end_test_config config,
   grpc_op* op;
   grpc_call* c;
   grpc_end2end_test_fixture f = begin_test(config, "test_cancel_after_invoke",
-                                           mode, test_ops, NULL, NULL);
+                                           mode, test_ops, nullptr, nullptr);
   cq_verifier* cqv = cq_verifier_create(f.cq);
   grpc_metadata_array initial_metadata_recv;
   grpc_metadata_array trailing_metadata_recv;
@@ -104,7 +104,7 @@ static void test_cancel_after_invoke(grpc_end2end_test_config config,
   grpc_status_code status;
   grpc_call_error error;
   grpc_slice details;
-  grpc_byte_buffer* response_payload_recv = NULL;
+  grpc_byte_buffer* response_payload_recv = nullptr;
   grpc_slice request_payload_slice =
       grpc_slice_from_copied_string("hello world");
   grpc_byte_buffer* request_payload =
@@ -112,10 +112,10 @@ static void test_cancel_after_invoke(grpc_end2end_test_config config,
 
   gpr_timespec deadline = five_seconds_from_now();
   c = grpc_channel_create_call(
-      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+      f.client, nullptr, GRPC_PROPAGATE_DEFAULTS, f.cq,
       grpc_slice_from_static_string("/foo"),
       get_host_override_slice("foo.test.google.fr:1234", config), deadline,
-      NULL);
+      nullptr);
   GPR_ASSERT(c);
 
   grpc_metadata_array_init(&initial_metadata_recv);
@@ -130,36 +130,36 @@ static void test_cancel_after_invoke(grpc_end2end_test_config config,
   op->data.recv_status_on_client.status = &status;
   op->data.recv_status_on_client.status_details = &details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_INITIAL_METADATA;
   op->data.recv_initial_metadata.recv_initial_metadata = &initial_metadata_recv;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
   op->data.send_initial_metadata.count = 0;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_MESSAGE;
   op->data.send_message.send_message = request_payload;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_CLOSE_FROM_CLIENT;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_MESSAGE;
   op->data.recv_message.recv_message = &response_payload_recv;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(c, ops, test_ops, tag(1), NULL);
+  error = grpc_call_start_batch(c, ops, test_ops, tag(1), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
-  GPR_ASSERT(GRPC_CALL_OK == mode.initiate_cancel(c, NULL));
+  GPR_ASSERT(GRPC_CALL_OK == mode.initiate_cancel(c, nullptr));
 
   CQ_EXPECT_COMPLETION(cqv, tag(1), 1);
   cq_verify(cqv);
diff --git a/test/core/end2end/tests/cancel_after_round_trip.cc b/test/core/end2end/tests/cancel_after_round_trip.cc
index 35b5214fac..6d547662dd 100644
--- a/test/core/end2end/tests/cancel_after_round_trip.cc
+++ b/test/core/end2end/tests/cancel_after_round_trip.cc
@@ -63,7 +63,7 @@ static gpr_timespec five_seconds_from_now(void) {
 static void drain_cq(grpc_completion_queue* cq) {
   grpc_event ev;
   do {
-    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), NULL);
+    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), nullptr);
   } while (ev.type != GRPC_QUEUE_SHUTDOWN);
 }
 
@@ -72,16 +72,16 @@ static void shutdown_server(grpc_end2end_test_fixture* f) {
   grpc_server_shutdown_and_notify(f->server, f->shutdown_cq, tag(1000));
   GPR_ASSERT(grpc_completion_queue_pluck(f->shutdown_cq, tag(1000),
                                          grpc_timeout_seconds_to_deadline(5),
-                                         NULL)
+                                         nullptr)
                  .type == GRPC_OP_COMPLETE);
   grpc_server_destroy(f->server);
-  f->server = NULL;
+  f->server = nullptr;
 }
 
 static void shutdown_client(grpc_end2end_test_fixture* f) {
   if (!f->client) return;
   grpc_channel_destroy(f->client);
-  f->client = NULL;
+  f->client = nullptr;
 }
 
 static void end_test(grpc_end2end_test_fixture* f) {
@@ -109,8 +109,8 @@ static void test_cancel_after_round_trip(grpc_end2end_test_config config,
   grpc_status_code status;
   grpc_call_error error;
   grpc_slice details;
-  grpc_byte_buffer* request_payload_recv = NULL;
-  grpc_byte_buffer* response_payload_recv = NULL;
+  grpc_byte_buffer* request_payload_recv = nullptr;
+  grpc_byte_buffer* response_payload_recv = nullptr;
   grpc_slice request_payload_slice =
       grpc_slice_from_copied_string("hello world");
   grpc_slice response_payload_slice =
@@ -123,7 +123,7 @@ static void test_cancel_after_round_trip(grpc_end2end_test_config config,
       grpc_raw_byte_buffer_create(&response_payload_slice, 1);
   int was_cancelled = 2;
 
-  grpc_channel_args* args = NULL;
+  grpc_channel_args* args = nullptr;
   if (use_service_config) {
     grpc_arg arg;
     arg.type = GRPC_ARG_STRING;
@@ -141,17 +141,17 @@ static void test_cancel_after_round_trip(grpc_end2end_test_config config,
   }
 
   grpc_end2end_test_fixture f = begin_test(
-      config, "cancel_after_round_trip", mode, use_service_config, args, NULL);
+      config, "cancel_after_round_trip", mode, use_service_config, args, nullptr);
   cq_verifier* cqv = cq_verifier_create(f.cq);
 
   gpr_timespec deadline = use_service_config
                               ? gpr_inf_future(GPR_CLOCK_MONOTONIC)
                               : five_seconds_from_now();
   c = grpc_channel_create_call(
-      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+      f.client, nullptr, GRPC_PROPAGATE_DEFAULTS, f.cq,
       grpc_slice_from_static_string("/service/method"),
       get_host_override_slice("foo.test.google.fr:1234", config), deadline,
-      NULL);
+      nullptr);
   GPR_ASSERT(c);
 
   grpc_metadata_array_init(&initial_metadata_recv);
@@ -164,24 +164,24 @@ static void test_cancel_after_round_trip(grpc_end2end_test_config config,
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
   op->data.send_initial_metadata.count = 0;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_MESSAGE;
   op->data.send_message.send_message = request_payload;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_INITIAL_METADATA;
   op->data.recv_initial_metadata.recv_initial_metadata = &initial_metadata_recv;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_MESSAGE;
   op->data.recv_message.recv_message = &response_payload_recv;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), NULL);
+  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   error =
@@ -196,19 +196,19 @@ static void test_cancel_after_round_trip(grpc_end2end_test_config config,
   op->op = GRPC_OP_RECV_MESSAGE;
   op->data.recv_message.recv_message = &request_payload_recv;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
   op->data.send_initial_metadata.count = 0;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_MESSAGE;
   op->data.send_message.send_message = response_payload1;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(102), NULL);
+  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(102), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   CQ_EXPECT_COMPLETION(cqv, tag(102), 1);
@@ -217,8 +217,8 @@ static void test_cancel_after_round_trip(grpc_end2end_test_config config,
 
   grpc_byte_buffer_destroy(request_payload_recv);
   grpc_byte_buffer_destroy(response_payload_recv);
-  request_payload_recv = NULL;
-  response_payload_recv = NULL;
+  request_payload_recv = nullptr;
+  response_payload_recv = nullptr;
 
   memset(ops, 0, sizeof(ops));
   op = ops;
@@ -227,31 +227,31 @@ static void test_cancel_after_round_trip(grpc_end2end_test_config config,
   op->data.recv_status_on_client.status = &status;
   op->data.recv_status_on_client.status_details = &details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_MESSAGE;
   op->data.recv_message.recv_message = &response_payload_recv;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(2), NULL);
+  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(2), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
-  GPR_ASSERT(GRPC_CALL_OK == mode.initiate_cancel(c, NULL));
+  GPR_ASSERT(GRPC_CALL_OK == mode.initiate_cancel(c, nullptr));
 
   memset(ops, 0, sizeof(ops));
   op = ops;
   op->op = GRPC_OP_RECV_CLOSE_ON_SERVER;
   op->data.recv_close_on_server.cancelled = &was_cancelled;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_MESSAGE;
   op->data.send_message.send_message = response_payload2;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(103), NULL);
+  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(103), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   CQ_EXPECT_COMPLETION(cqv, tag(2), 1);
@@ -276,7 +276,7 @@ static void test_cancel_after_round_trip(grpc_end2end_test_config config,
   grpc_call_unref(c);
   grpc_call_unref(s);
 
-  if (args != NULL) {
+  if (args != nullptr) {
     grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
     grpc_channel_args_destroy(&exec_ctx, args);
     grpc_exec_ctx_finish(&exec_ctx);
diff --git a/test/core/end2end/tests/cancel_before_invoke.cc b/test/core/end2end/tests/cancel_before_invoke.cc
index 9504aae5e6..1112375176 100644
--- a/test/core/end2end/tests/cancel_before_invoke.cc
+++ b/test/core/end2end/tests/cancel_before_invoke.cc
@@ -55,7 +55,7 @@ static gpr_timespec five_seconds_from_now(void) {
 static void drain_cq(grpc_completion_queue* cq) {
   grpc_event ev;
   do {
-    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), NULL);
+    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), nullptr);
   } while (ev.type != GRPC_QUEUE_SHUTDOWN);
 }
 
@@ -64,16 +64,16 @@ static void shutdown_server(grpc_end2end_test_fixture* f) {
   grpc_server_shutdown_and_notify(f->server, f->shutdown_cq, tag(1000));
   GPR_ASSERT(grpc_completion_queue_pluck(f->shutdown_cq, tag(1000),
                                          grpc_timeout_seconds_to_deadline(5),
-                                         NULL)
+                                         nullptr)
                  .type == GRPC_OP_COMPLETE);
   grpc_server_destroy(f->server);
-  f->server = NULL;
+  f->server = nullptr;
 }
 
 static void shutdown_client(grpc_end2end_test_fixture* f) {
   if (!f->client) return;
   grpc_channel_destroy(f->client);
-  f->client = NULL;
+  f->client = nullptr;
 }
 
 static void end_test(grpc_end2end_test_fixture* f) {
@@ -93,7 +93,7 @@ static void test_cancel_before_invoke(grpc_end2end_test_config config,
   grpc_op* op;
   grpc_call* c;
   grpc_end2end_test_fixture f =
-      begin_test(config, "cancel_before_invoke", test_ops, NULL, NULL);
+      begin_test(config, "cancel_before_invoke", test_ops, nullptr, nullptr);
   cq_verifier* cqv = cq_verifier_create(f.cq);
   grpc_metadata_array initial_metadata_recv;
   grpc_metadata_array trailing_metadata_recv;
@@ -102,7 +102,7 @@ static void test_cancel_before_invoke(grpc_end2end_test_config config,
   grpc_status_code status;
   grpc_call_error error;
   grpc_slice details;
-  grpc_byte_buffer* response_payload_recv = NULL;
+  grpc_byte_buffer* response_payload_recv = nullptr;
   grpc_slice request_payload_slice =
       grpc_slice_from_copied_string("hello world");
   grpc_byte_buffer* request_payload =
@@ -110,13 +110,13 @@ static void test_cancel_before_invoke(grpc_end2end_test_config config,
 
   gpr_timespec deadline = five_seconds_from_now();
   c = grpc_channel_create_call(
-      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+      f.client, nullptr, GRPC_PROPAGATE_DEFAULTS, f.cq,
       grpc_slice_from_static_string("/foo"),
       get_host_override_slice("foo.test.google.fr:1234", config), deadline,
-      NULL);
+      nullptr);
   GPR_ASSERT(c);
 
-  GPR_ASSERT(GRPC_CALL_OK == grpc_call_cancel(c, NULL));
+  GPR_ASSERT(GRPC_CALL_OK == grpc_call_cancel(c, nullptr));
 
   grpc_metadata_array_init(&initial_metadata_recv);
   grpc_metadata_array_init(&trailing_metadata_recv);
@@ -130,33 +130,33 @@ static void test_cancel_before_invoke(grpc_end2end_test_config config,
   op->data.recv_status_on_client.status = &status;
   op->data.recv_status_on_client.status_details = &details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
   op->data.send_initial_metadata.count = 0;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_MESSAGE;
   op->data.send_message.send_message = request_payload;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_CLOSE_FROM_CLIENT;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_INITIAL_METADATA;
   op->data.recv_initial_metadata.recv_initial_metadata = &initial_metadata_recv;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_MESSAGE;
   op->data.recv_message.recv_message = &response_payload_recv;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(c, ops, test_ops, tag(1), NULL);
+  error = grpc_call_start_batch(c, ops, test_ops, tag(1), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   CQ_EXPECT_COMPLETION(cqv, tag(1), 1);
diff --git a/test/core/end2end/tests/cancel_in_a_vacuum.cc b/test/core/end2end/tests/cancel_in_a_vacuum.cc
index 090ee2fbb2..a6c534eb08 100644
--- a/test/core/end2end/tests/cancel_in_a_vacuum.cc
+++ b/test/core/end2end/tests/cancel_in_a_vacuum.cc
@@ -56,7 +56,7 @@ static gpr_timespec five_seconds_from_now(void) {
 static void drain_cq(grpc_completion_queue* cq) {
   grpc_event ev;
   do {
-    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), NULL);
+    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), nullptr);
   } while (ev.type != GRPC_QUEUE_SHUTDOWN);
 }
 
@@ -65,16 +65,16 @@ static void shutdown_server(grpc_end2end_test_fixture* f) {
   grpc_server_shutdown_and_notify(f->server, f->shutdown_cq, tag(1000));
   GPR_ASSERT(grpc_completion_queue_pluck(f->shutdown_cq, tag(1000),
                                          grpc_timeout_seconds_to_deadline(5),
-                                         NULL)
+                                         nullptr)
                  .type == GRPC_OP_COMPLETE);
   grpc_server_destroy(f->server);
-  f->server = NULL;
+  f->server = nullptr;
 }
 
 static void shutdown_client(grpc_end2end_test_fixture* f) {
   if (!f->client) return;
   grpc_channel_destroy(f->client);
-  f->client = NULL;
+  f->client = nullptr;
 }
 
 static void end_test(grpc_end2end_test_fixture* f) {
@@ -92,18 +92,18 @@ static void test_cancel_in_a_vacuum(grpc_end2end_test_config config,
                                     cancellation_mode mode) {
   grpc_call* c;
   grpc_end2end_test_fixture f =
-      begin_test(config, "test_cancel_in_a_vacuum", mode, NULL, NULL);
+      begin_test(config, "test_cancel_in_a_vacuum", mode, nullptr, nullptr);
   cq_verifier* v_client = cq_verifier_create(f.cq);
 
   gpr_timespec deadline = five_seconds_from_now();
   c = grpc_channel_create_call(
-      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+      f.client, nullptr, GRPC_PROPAGATE_DEFAULTS, f.cq,
       grpc_slice_from_static_string("/foo"),
       get_host_override_slice("foo.test.google.fr:1234", config), deadline,
-      NULL);
+      nullptr);
   GPR_ASSERT(c);
 
-  GPR_ASSERT(GRPC_CALL_OK == mode.initiate_cancel(c, NULL));
+  GPR_ASSERT(GRPC_CALL_OK == mode.initiate_cancel(c, nullptr));
 
   grpc_call_unref(c);
 
diff --git a/test/core/end2end/tests/cancel_with_status.cc b/test/core/end2end/tests/cancel_with_status.cc
index bc3c4c3ebd..cc5498d6b3 100644
--- a/test/core/end2end/tests/cancel_with_status.cc
+++ b/test/core/end2end/tests/cancel_with_status.cc
@@ -58,7 +58,7 @@ static gpr_timespec five_seconds_from_now(void) {
 static void drain_cq(grpc_completion_queue* cq) {
   grpc_event ev;
   do {
-    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), NULL);
+    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), nullptr);
   } while (ev.type != GRPC_QUEUE_SHUTDOWN);
 }
 
@@ -66,17 +66,17 @@ static void shutdown_server(grpc_end2end_test_fixture* f) {
   if (!f->server) return;
   grpc_server_shutdown_and_notify(f->server, f->cq, tag(1000));
   grpc_event ev = grpc_completion_queue_next(
-      f->cq, grpc_timeout_seconds_to_deadline(5), NULL);
+      f->cq, grpc_timeout_seconds_to_deadline(5), nullptr);
   GPR_ASSERT(ev.type == GRPC_OP_COMPLETE);
   GPR_ASSERT(ev.tag == tag(1000));
   grpc_server_destroy(f->server);
-  f->server = NULL;
+  f->server = nullptr;
 }
 
 static void shutdown_client(grpc_end2end_test_fixture* f) {
   if (!f->client) return;
   grpc_channel_destroy(f->client);
-  f->client = NULL;
+  f->client = nullptr;
 }
 
 static void end_test(grpc_end2end_test_fixture* f) {
@@ -105,10 +105,10 @@ static void simple_request_body(grpc_end2end_test_config config,
 
   gpr_timespec deadline = five_seconds_from_now();
   c = grpc_channel_create_call(
-      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+      f.client, nullptr, GRPC_PROPAGATE_DEFAULTS, f.cq,
       grpc_slice_from_static_string("/foo"),
       get_host_override_slice("foo.test.google.fr:1234", config), deadline,
-      NULL);
+      nullptr);
   GPR_ASSERT(c);
 
   grpc_metadata_array_init(&initial_metadata_recv);
@@ -121,29 +121,29 @@ static void simple_request_body(grpc_end2end_test_config config,
   op->data.recv_status_on_client.status = &status;
   op->data.recv_status_on_client.status_details = &details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_INITIAL_METADATA;
   op->data.recv_initial_metadata.recv_initial_metadata = &initial_metadata_recv;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
   op->data.send_initial_metadata.count = 0;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_CLOSE_FROM_CLIENT;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   GPR_ASSERT(num_ops <= (size_t)(op - ops));
-  error = grpc_call_start_batch(c, ops, num_ops, tag(1), NULL);
+  error = grpc_call_start_batch(c, ops, num_ops, tag(1), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   char* dynamic_string = gpr_strdup("xyz");
   grpc_call_cancel_with_status(c, GRPC_STATUS_UNIMPLEMENTED,
-                               (const char*)dynamic_string, NULL);
+                               (const char*)dynamic_string, nullptr);
   // The API of \a description allows for it to be a dynamic/non-const
   // string, test this guarantee.
   gpr_free(dynamic_string);
@@ -167,7 +167,7 @@ static void test_invoke_simple_request(grpc_end2end_test_config config,
                                        size_t num_ops) {
   grpc_end2end_test_fixture f;
 
-  f = begin_test(config, "test_invoke_simple_request", num_ops, NULL, NULL);
+  f = begin_test(config, "test_invoke_simple_request", num_ops, nullptr, nullptr);
   simple_request_body(config, f, num_ops);
   end_test(&f);
   config.tear_down_data(&f);
diff --git a/test/core/end2end/tests/compressed_payload.cc b/test/core/end2end/tests/compressed_payload.cc
index b5fc1898b5..8ffcbe89cb 100644
--- a/test/core/end2end/tests/compressed_payload.cc
+++ b/test/core/end2end/tests/compressed_payload.cc
@@ -61,7 +61,7 @@ static gpr_timespec five_seconds_from_now(void) {
 static void drain_cq(grpc_completion_queue* cq) {
   grpc_event ev;
   do {
-    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), NULL);
+    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), nullptr);
   } while (ev.type != GRPC_QUEUE_SHUTDOWN);
 }
 
@@ -70,16 +70,16 @@ static void shutdown_server(grpc_end2end_test_fixture* f) {
   grpc_server_shutdown_and_notify(f->server, f->shutdown_cq, tag(1000));
   GPR_ASSERT(grpc_completion_queue_pluck(f->shutdown_cq, tag(1000),
                                          grpc_timeout_seconds_to_deadline(5),
-                                         NULL)
+                                         nullptr)
                  .type == GRPC_OP_COMPLETE);
   grpc_server_destroy(f->server);
-  f->server = NULL;
+  f->server = nullptr;
 }
 
 static void shutdown_client(grpc_end2end_test_fixture* f) {
   if (!f->client) return;
   grpc_channel_destroy(f->client);
-  f->client = NULL;
+  f->client = nullptr;
 }
 
 static void end_test(grpc_end2end_test_fixture* f) {
@@ -110,7 +110,7 @@ static void request_for_disabled_algorithm(
   grpc_metadata_array initial_metadata_recv;
   grpc_metadata_array trailing_metadata_recv;
   grpc_metadata_array request_metadata_recv;
-  grpc_byte_buffer* request_payload_recv = NULL;
+  grpc_byte_buffer* request_payload_recv = nullptr;
   grpc_call_details call_details;
   grpc_status_code status;
   grpc_call_error error;
@@ -125,9 +125,9 @@ static void request_for_disabled_algorithm(
   request_payload = grpc_raw_byte_buffer_create(&request_payload_slice, 1);
 
   client_args = grpc_channel_args_set_compression_algorithm(
-      NULL, requested_client_compression_algorithm);
+      nullptr, requested_client_compression_algorithm);
   server_args =
-      grpc_channel_args_set_compression_algorithm(NULL, GRPC_COMPRESS_NONE);
+      grpc_channel_args_set_compression_algorithm(nullptr, GRPC_COMPRESS_NONE);
   {
     grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
     server_args = grpc_channel_args_compression_algorithm_set_state(
@@ -140,10 +140,10 @@ static void request_for_disabled_algorithm(
 
   gpr_timespec deadline = five_seconds_from_now();
   c = grpc_channel_create_call(
-      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+      f.client, nullptr, GRPC_PROPAGATE_DEFAULTS, f.cq,
       grpc_slice_from_static_string("/foo"),
       get_host_override_slice("foo.test.google.fr:1234", config), deadline,
-      NULL);
+      nullptr);
   GPR_ASSERT(c);
 
   grpc_metadata_array_init(&initial_metadata_recv);
@@ -159,37 +159,37 @@ static void request_for_disabled_algorithm(
   memset(ops, 0, sizeof(ops));
   op = ops;
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
-  if (client_metadata != NULL) {
+  if (client_metadata != nullptr) {
     op->data.send_initial_metadata.count = 1;
     op->data.send_initial_metadata.metadata = client_metadata;
   } else {
     op->data.send_initial_metadata.count = 0;
   }
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_MESSAGE;
   op->data.send_message.send_message = request_payload;
   op->flags = send_flags_bitmask;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_CLOSE_FROM_CLIENT;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_INITIAL_METADATA;
   op->data.recv_initial_metadata.recv_initial_metadata = &initial_metadata_recv;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_STATUS_ON_CLIENT;
   op->data.recv_status_on_client.trailing_metadata = &trailing_metadata_recv;
   op->data.recv_status_on_client.status = &status;
   op->data.recv_status_on_client.status_details = &details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), NULL);
+  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   CQ_EXPECT_COMPLETION(cqv, tag(101), true);
@@ -200,14 +200,14 @@ static void request_for_disabled_algorithm(
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
   op->data.send_initial_metadata.count = 0;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_MESSAGE;
   op->data.recv_message.recv_message = &request_payload_recv;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(102), NULL);
+  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(102), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   CQ_EXPECT_COMPLETION(cqv, tag(102), false);
@@ -216,9 +216,9 @@ static void request_for_disabled_algorithm(
   op->op = GRPC_OP_RECV_CLOSE_ON_SERVER;
   op->data.recv_close_on_server.cancelled = &was_cancelled;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(103), NULL);
+  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(103), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   CQ_EXPECT_COMPLETION(cqv, tag(103), true);
@@ -229,9 +229,9 @@ static void request_for_disabled_algorithm(
   /* with a certain error */
   GPR_ASSERT(status == expected_error);
 
-  const char* algo_name = NULL;
+  const char* algo_name = nullptr;
   GPR_ASSERT(grpc_compression_algorithm_name(algorithm_to_disable, &algo_name));
-  char* expected_details = NULL;
+  char* expected_details = nullptr;
   gpr_asprintf(&expected_details, "Compression algorithm '%s' is disabled.",
                algo_name);
   /* and we expect a specific reason for it */
@@ -280,7 +280,7 @@ static void request_with_payload_template(
   grpc_call* c;
   grpc_call* s;
   grpc_slice request_payload_slice;
-  grpc_byte_buffer* request_payload = NULL;
+  grpc_byte_buffer* request_payload = nullptr;
   grpc_channel_args* client_args;
   grpc_channel_args* server_args;
   grpc_end2end_test_fixture f;
@@ -289,7 +289,7 @@ static void request_with_payload_template(
   grpc_metadata_array initial_metadata_recv;
   grpc_metadata_array trailing_metadata_recv;
   grpc_metadata_array request_metadata_recv;
-  grpc_byte_buffer* request_payload_recv = NULL;
+  grpc_byte_buffer* request_payload_recv = nullptr;
   grpc_byte_buffer* response_payload;
   grpc_byte_buffer* response_payload_recv;
   grpc_call_details call_details;
@@ -312,19 +312,19 @@ static void request_with_payload_template(
       grpc_slice_from_copied_string(response_str);
 
   client_args = grpc_channel_args_set_compression_algorithm(
-      NULL, default_client_channel_compression_algorithm);
+      nullptr, default_client_channel_compression_algorithm);
   server_args = grpc_channel_args_set_compression_algorithm(
-      NULL, default_server_channel_compression_algorithm);
+      nullptr, default_server_channel_compression_algorithm);
 
   f = begin_test(config, test_name, client_args, server_args);
   cqv = cq_verifier_create(f.cq);
 
   gpr_timespec deadline = five_seconds_from_now();
   c = grpc_channel_create_call(
-      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+      f.client, nullptr, GRPC_PROPAGATE_DEFAULTS, f.cq,
       grpc_slice_from_static_string("/foo"),
       get_host_override_slice("foo.test.google.fr:1234", config), deadline,
-      NULL);
+      nullptr);
   GPR_ASSERT(c);
 
   grpc_metadata_array_init(&initial_metadata_recv);
@@ -339,9 +339,9 @@ static void request_with_payload_template(
     op->op = GRPC_OP_SEND_MESSAGE;
     op->data.send_message.send_message = request_payload;
     op->flags = client_send_flags_bitmask;
-    op->reserved = NULL;
+    op->reserved = nullptr;
     op++;
-    error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(2), NULL);
+    error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(2), nullptr);
     GPR_ASSERT(GRPC_CALL_OK == error);
     CQ_EXPECT_COMPLETION(cqv, tag(2), true);
   }
@@ -349,28 +349,28 @@ static void request_with_payload_template(
   memset(ops, 0, sizeof(ops));
   op = ops;
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
-  if (client_init_metadata != NULL) {
+  if (client_init_metadata != nullptr) {
     op->data.send_initial_metadata.count = 1;
     op->data.send_initial_metadata.metadata = client_init_metadata;
   } else {
     op->data.send_initial_metadata.count = 0;
   }
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_INITIAL_METADATA;
   op->data.recv_initial_metadata.recv_initial_metadata = &initial_metadata_recv;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_STATUS_ON_CLIENT;
   op->data.recv_status_on_client.trailing_metadata = &trailing_metadata_recv;
   op->data.recv_status_on_client.status = &status;
   op->data.recv_status_on_client.status_details = &details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), NULL);
+  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   error =
@@ -399,14 +399,14 @@ static void request_with_payload_template(
         server_compression_level;
   }
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_CLOSE_ON_SERVER;
   op->data.recv_close_on_server.cancelled = &was_cancelled;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(101), NULL);
+  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(101), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   for (int i = 0; i < 2; i++) {
@@ -419,9 +419,9 @@ static void request_with_payload_template(
       op->op = GRPC_OP_SEND_MESSAGE;
       op->data.send_message.send_message = request_payload;
       op->flags = client_send_flags_bitmask;
-      op->reserved = NULL;
+      op->reserved = nullptr;
       op++;
-      error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(2), NULL);
+      error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(2), nullptr);
       GPR_ASSERT(GRPC_CALL_OK == error);
       CQ_EXPECT_COMPLETION(cqv, tag(2), 1);
     }
@@ -431,9 +431,9 @@ static void request_with_payload_template(
     op->op = GRPC_OP_RECV_MESSAGE;
     op->data.recv_message.recv_message = &request_payload_recv;
     op->flags = 0;
-    op->reserved = NULL;
+    op->reserved = nullptr;
     op++;
-    error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(102), NULL);
+    error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(102), nullptr);
     GPR_ASSERT(GRPC_CALL_OK == error);
 
     CQ_EXPECT_COMPLETION(cqv, tag(102), 1);
@@ -449,9 +449,9 @@ static void request_with_payload_template(
     op->op = GRPC_OP_SEND_MESSAGE;
     op->data.send_message.send_message = response_payload;
     op->flags = 0;
-    op->reserved = NULL;
+    op->reserved = nullptr;
     op++;
-    error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(103), NULL);
+    error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(103), nullptr);
     GPR_ASSERT(GRPC_CALL_OK == error);
 
     memset(ops, 0, sizeof(ops));
@@ -459,9 +459,9 @@ static void request_with_payload_template(
     op->op = GRPC_OP_RECV_MESSAGE;
     op->data.recv_message.recv_message = &response_payload_recv;
     op->flags = 0;
-    op->reserved = NULL;
+    op->reserved = nullptr;
     op++;
-    error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(3), NULL);
+    error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(3), nullptr);
     GPR_ASSERT(GRPC_CALL_OK == error);
 
     CQ_EXPECT_COMPLETION(cqv, tag(103), 1);
@@ -493,9 +493,9 @@ static void request_with_payload_template(
   op = ops;
   op->op = GRPC_OP_SEND_CLOSE_FROM_CLIENT;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(4), NULL);
+  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(4), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   memset(ops, 0, sizeof(ops));
@@ -506,9 +506,9 @@ static void request_with_payload_template(
   grpc_slice status_details = grpc_slice_from_static_string("xyz");
   op->data.send_status_from_server.status_details = &status_details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(104), NULL);
+  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(104), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   CQ_EXPECT_COMPLETION(cqv, tag(1), 1);
@@ -551,7 +551,7 @@ static void test_invoke_request_with_exceptionally_uncompressed_payload(
   request_with_payload_template(
       config, "test_invoke_request_with_exceptionally_uncompressed_payload",
       GRPC_WRITE_NO_COMPRESS, GRPC_COMPRESS_GZIP, GRPC_COMPRESS_GZIP,
-      GRPC_COMPRESS_NONE, GRPC_COMPRESS_GZIP, NULL, false,
+      GRPC_COMPRESS_NONE, GRPC_COMPRESS_GZIP, nullptr, false,
       /* ignored */ GRPC_COMPRESS_LEVEL_NONE, false);
 }
 
@@ -560,7 +560,7 @@ static void test_invoke_request_with_uncompressed_payload(
   request_with_payload_template(
       config, "test_invoke_request_with_uncompressed_payload", 0,
       GRPC_COMPRESS_NONE, GRPC_COMPRESS_NONE, GRPC_COMPRESS_NONE,
-      GRPC_COMPRESS_NONE, NULL, false, /* ignored */ GRPC_COMPRESS_LEVEL_NONE,
+      GRPC_COMPRESS_NONE, nullptr, false, /* ignored */ GRPC_COMPRESS_LEVEL_NONE,
       false);
 }
 
@@ -569,7 +569,7 @@ static void test_invoke_request_with_compressed_payload(
   request_with_payload_template(
       config, "test_invoke_request_with_compressed_payload", 0,
       GRPC_COMPRESS_GZIP, GRPC_COMPRESS_GZIP, GRPC_COMPRESS_GZIP,
-      GRPC_COMPRESS_GZIP, NULL, false, /* ignored */ GRPC_COMPRESS_LEVEL_NONE,
+      GRPC_COMPRESS_GZIP, nullptr, false, /* ignored */ GRPC_COMPRESS_LEVEL_NONE,
       false);
 }
 
@@ -578,7 +578,7 @@ static void test_invoke_request_with_send_message_before_initial_metadata(
   request_with_payload_template(
       config, "test_invoke_request_with_compressed_payload", 0,
       GRPC_COMPRESS_GZIP, GRPC_COMPRESS_GZIP, GRPC_COMPRESS_GZIP,
-      GRPC_COMPRESS_GZIP, NULL, false, /* ignored */ GRPC_COMPRESS_LEVEL_NONE,
+      GRPC_COMPRESS_GZIP, nullptr, false, /* ignored */ GRPC_COMPRESS_LEVEL_NONE,
       true);
 }
 
@@ -587,7 +587,7 @@ static void test_invoke_request_with_server_level(
   request_with_payload_template(
       config, "test_invoke_request_with_server_level", 0, GRPC_COMPRESS_NONE,
       GRPC_COMPRESS_NONE, GRPC_COMPRESS_NONE, GRPC_COMPRESS_NONE /* ignored */,
-      NULL, true, GRPC_COMPRESS_LEVEL_HIGH, false);
+      nullptr, true, GRPC_COMPRESS_LEVEL_HIGH, false);
 }
 
 static void test_invoke_request_with_compressed_payload_md_override(
@@ -632,7 +632,7 @@ static void test_invoke_request_with_disabled_algorithm(
     grpc_end2end_test_config config) {
   request_for_disabled_algorithm(
       config, "test_invoke_request_with_disabled_algorithm", 0,
-      GRPC_COMPRESS_GZIP, GRPC_COMPRESS_GZIP, GRPC_STATUS_UNIMPLEMENTED, NULL);
+      GRPC_COMPRESS_GZIP, GRPC_COMPRESS_GZIP, GRPC_STATUS_UNIMPLEMENTED, nullptr);
 }
 
 void compressed_payload(grpc_end2end_test_config config) {
diff --git a/test/core/end2end/tests/connectivity.cc b/test/core/end2end/tests/connectivity.cc
index 4f302d11dc..2ea4ca81f5 100644
--- a/test/core/end2end/tests/connectivity.cc
+++ b/test/core/end2end/tests/connectivity.cc
@@ -39,14 +39,14 @@ static void child_thread(void* arg) {
   gpr_event_set(&ce->started, (void*)1);
   gpr_log(GPR_DEBUG, "verifying");
   ev = grpc_completion_queue_next(ce->cq, gpr_inf_future(GPR_CLOCK_MONOTONIC),
-                                  NULL);
+                                  nullptr);
   GPR_ASSERT(ev.type == GRPC_OP_COMPLETE);
   GPR_ASSERT(ev.tag == tag(1));
   GPR_ASSERT(ev.success == 0);
 }
 
 static void test_connectivity(grpc_end2end_test_config config) {
-  grpc_end2end_test_fixture f = config.create_fixture(NULL, NULL);
+  grpc_end2end_test_fixture f = config.create_fixture(nullptr, nullptr);
   grpc_connectivity_state state;
   cq_verifier* cqv = cq_verifier_create(f.cq);
   child_events ce;
@@ -115,7 +115,7 @@ static void test_connectivity(grpc_end2end_test_config config) {
   gpr_log(GPR_DEBUG, "*** STARTING SERVER ***");
 
   /* now let's bring up a server to connect to */
-  config.init_server(&f, NULL);
+  config.init_server(&f, nullptr);
 
   gpr_log(GPR_DEBUG, "*** STARTED SERVER ***");
 
diff --git a/test/core/end2end/tests/default_host.cc b/test/core/end2end/tests/default_host.cc
index 166f22aec9..85f92b0ab0 100644
--- a/test/core/end2end/tests/default_host.cc
+++ b/test/core/end2end/tests/default_host.cc
@@ -55,7 +55,7 @@ static gpr_timespec five_seconds_from_now(void) {
 static void drain_cq(grpc_completion_queue* cq) {
   grpc_event ev;
   do {
-    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), NULL);
+    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), nullptr);
   } while (ev.type != GRPC_QUEUE_SHUTDOWN);
 }
 
@@ -64,16 +64,16 @@ static void shutdown_server(grpc_end2end_test_fixture* f) {
   grpc_server_shutdown_and_notify(f->server, f->shutdown_cq, tag(1000));
   GPR_ASSERT(grpc_completion_queue_pluck(f->shutdown_cq, tag(1000),
                                          grpc_timeout_seconds_to_deadline(5),
-                                         NULL)
+                                         nullptr)
                  .type == GRPC_OP_COMPLETE);
   grpc_server_destroy(f->server);
-  f->server = NULL;
+  f->server = nullptr;
 }
 
 static void shutdown_client(grpc_end2end_test_fixture* f) {
   if (!f->client) return;
   grpc_channel_destroy(f->client);
-  f->client = NULL;
+  f->client = nullptr;
 }
 
 static void end_test(grpc_end2end_test_fixture* f) {
@@ -103,13 +103,13 @@ static void simple_request_body(grpc_end2end_test_fixture f) {
   char* peer;
 
   gpr_timespec deadline = five_seconds_from_now();
-  c = grpc_channel_create_call(f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
-                               grpc_slice_from_static_string("/foo"), NULL,
-                               deadline, NULL);
+  c = grpc_channel_create_call(f.client, nullptr, GRPC_PROPAGATE_DEFAULTS, f.cq,
+                               grpc_slice_from_static_string("/foo"), nullptr,
+                               deadline, nullptr);
   GPR_ASSERT(c);
 
   peer = grpc_call_get_peer(c);
-  GPR_ASSERT(peer != NULL);
+  GPR_ASSERT(peer != nullptr);
   gpr_log(GPR_DEBUG, "client_peer_before_call=%s", peer);
   gpr_free(peer);
 
@@ -123,25 +123,25 @@ static void simple_request_body(grpc_end2end_test_fixture f) {
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
   op->data.send_initial_metadata.count = 0;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_CLOSE_FROM_CLIENT;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_INITIAL_METADATA;
   op->data.recv_initial_metadata.recv_initial_metadata = &initial_metadata_recv;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_STATUS_ON_CLIENT;
   op->data.recv_status_on_client.trailing_metadata = &trailing_metadata_recv;
   op->data.recv_status_on_client.status = &status;
   op->data.recv_status_on_client.status_details = &details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), NULL);
+  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), nullptr);
   GPR_ASSERT(error == GRPC_CALL_OK);
 
   error =
@@ -152,11 +152,11 @@ static void simple_request_body(grpc_end2end_test_fixture f) {
   cq_verify(cqv);
 
   peer = grpc_call_get_peer(s);
-  GPR_ASSERT(peer != NULL);
+  GPR_ASSERT(peer != nullptr);
   gpr_log(GPR_DEBUG, "server_peer=%s", peer);
   gpr_free(peer);
   peer = grpc_call_get_peer(c);
-  GPR_ASSERT(peer != NULL);
+  GPR_ASSERT(peer != nullptr);
   gpr_log(GPR_DEBUG, "client_peer=%s", peer);
   gpr_free(peer);
 
@@ -165,7 +165,7 @@ static void simple_request_body(grpc_end2end_test_fixture f) {
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
   op->data.send_initial_metadata.count = 0;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_STATUS_FROM_SERVER;
   op->data.send_status_from_server.trailing_metadata_count = 0;
@@ -173,14 +173,14 @@ static void simple_request_body(grpc_end2end_test_fixture f) {
   grpc_slice status_details = grpc_slice_from_static_string("xyz");
   op->data.send_status_from_server.status_details = &status_details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_CLOSE_ON_SERVER;
   op->data.recv_close_on_server.cancelled = &was_cancelled;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(102), NULL);
+  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(102), nullptr);
   GPR_ASSERT(error == GRPC_CALL_OK);
 
   CQ_EXPECT_COMPLETION(cqv, tag(102), 1);
@@ -208,7 +208,7 @@ static void simple_request_body(grpc_end2end_test_fixture f) {
 static void test_invoke_simple_request(grpc_end2end_test_config config) {
   grpc_end2end_test_fixture f;
 
-  f = begin_test(config, "test_invoke_simple_request", NULL, NULL);
+  f = begin_test(config, "test_invoke_simple_request", nullptr, nullptr);
   simple_request_body(f);
   end_test(&f);
   config.tear_down_data(&f);
diff --git a/test/core/end2end/tests/disappearing_server.cc b/test/core/end2end/tests/disappearing_server.cc
index a0b34dd805..29fb19463f 100644
--- a/test/core/end2end/tests/disappearing_server.cc
+++ b/test/core/end2end/tests/disappearing_server.cc
@@ -41,20 +41,20 @@ static gpr_timespec five_seconds_from_now(void) {
 static void drain_cq(grpc_completion_queue* cq) {
   grpc_event ev;
   do {
-    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), NULL);
+    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), nullptr);
   } while (ev.type != GRPC_QUEUE_SHUTDOWN);
 }
 
 static void shutdown_server(grpc_end2end_test_fixture* f) {
   if (!f->server) return;
   grpc_server_destroy(f->server);
-  f->server = NULL;
+  f->server = nullptr;
 }
 
 static void shutdown_client(grpc_end2end_test_fixture* f) {
   if (!f->client) return;
   grpc_channel_destroy(f->client);
-  f->client = NULL;
+  f->client = nullptr;
 }
 
 static void end_test(grpc_end2end_test_fixture* f) {
@@ -87,10 +87,10 @@ static void do_request_and_shutdown_server(grpc_end2end_test_config config,
 
   gpr_timespec deadline = five_seconds_from_now();
   c = grpc_channel_create_call(
-      f->client, NULL, GRPC_PROPAGATE_DEFAULTS, f->cq,
+      f->client, nullptr, GRPC_PROPAGATE_DEFAULTS, f->cq,
       grpc_slice_from_static_string("/foo"),
       get_host_override_slice("foo.test.google.fr:1234", config), deadline,
-      NULL);
+      nullptr);
   GPR_ASSERT(c);
 
   grpc_metadata_array_init(&initial_metadata_recv);
@@ -103,25 +103,25 @@ static void do_request_and_shutdown_server(grpc_end2end_test_config config,
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
   op->data.send_initial_metadata.count = 0;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_CLOSE_FROM_CLIENT;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_INITIAL_METADATA;
   op->data.recv_initial_metadata.recv_initial_metadata = &initial_metadata_recv;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_STATUS_ON_CLIENT;
   op->data.recv_status_on_client.trailing_metadata = &trailing_metadata_recv;
   op->data.recv_status_on_client.status = &status;
   op->data.recv_status_on_client.status_details = &details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), NULL);
+  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   error =
@@ -140,7 +140,7 @@ static void do_request_and_shutdown_server(grpc_end2end_test_config config,
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
   op->data.send_initial_metadata.count = 0;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_STATUS_FROM_SERVER;
   op->data.send_status_from_server.trailing_metadata_count = 0;
@@ -148,14 +148,14 @@ static void do_request_and_shutdown_server(grpc_end2end_test_config config,
   grpc_slice status_details = grpc_slice_from_static_string("xyz");
   op->data.send_status_from_server.status_details = &status_details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_CLOSE_ON_SERVER;
   op->data.recv_close_on_server.cancelled = &was_cancelled;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(102), NULL);
+  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(102), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   CQ_EXPECT_COMPLETION(cqv, tag(102), 1);
@@ -181,19 +181,19 @@ static void do_request_and_shutdown_server(grpc_end2end_test_config config,
 }
 
 static void disappearing_server_test(grpc_end2end_test_config config) {
-  grpc_end2end_test_fixture f = config.create_fixture(NULL, NULL);
+  grpc_end2end_test_fixture f = config.create_fixture(nullptr, nullptr);
   cq_verifier* cqv = cq_verifier_create(f.cq);
 
   gpr_log(GPR_INFO, "Running test: %s/%s", "disappearing_server_test",
           config.name);
 
-  config.init_client(&f, NULL);
-  config.init_server(&f, NULL);
+  config.init_client(&f, nullptr);
+  config.init_server(&f, nullptr);
 
   do_request_and_shutdown_server(config, &f, cqv);
 
   /* now destroy and recreate the server */
-  config.init_server(&f, NULL);
+  config.init_server(&f, nullptr);
 
   do_request_and_shutdown_server(config, &f, cqv);
 
diff --git a/test/core/end2end/tests/empty_batch.cc b/test/core/end2end/tests/empty_batch.cc
index 59d0025239..b249c141de 100644
--- a/test/core/end2end/tests/empty_batch.cc
+++ b/test/core/end2end/tests/empty_batch.cc
@@ -55,7 +55,7 @@ static gpr_timespec five_seconds_from_now(void) {
 static void drain_cq(grpc_completion_queue* cq) {
   grpc_event ev;
   do {
-    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), NULL);
+    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), nullptr);
   } while (ev.type != GRPC_QUEUE_SHUTDOWN);
 }
 
@@ -64,16 +64,16 @@ static void shutdown_server(grpc_end2end_test_fixture* f) {
   grpc_server_shutdown_and_notify(f->server, f->shutdown_cq, tag(1000));
   GPR_ASSERT(grpc_completion_queue_pluck(f->shutdown_cq, tag(1000),
                                          grpc_timeout_seconds_to_deadline(5),
-                                         NULL)
+                                         nullptr)
                  .type == GRPC_OP_COMPLETE);
   grpc_server_destroy(f->server);
-  f->server = NULL;
+  f->server = nullptr;
 }
 
 static void shutdown_client(grpc_end2end_test_fixture* f) {
   if (!f->client) return;
   grpc_channel_destroy(f->client);
-  f->client = NULL;
+  f->client = nullptr;
 }
 
 static void end_test(grpc_end2end_test_fixture* f) {
@@ -91,17 +91,17 @@ static void empty_batch_body(grpc_end2end_test_config config,
   grpc_call* c;
   cq_verifier* cqv = cq_verifier_create(f.cq);
   grpc_call_error error;
-  grpc_op* op = NULL;
+  grpc_op* op = nullptr;
 
   gpr_timespec deadline = five_seconds_from_now();
   c = grpc_channel_create_call(
-      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+      f.client, nullptr, GRPC_PROPAGATE_DEFAULTS, f.cq,
       grpc_slice_from_static_string("/foo"),
       get_host_override_slice("foo.test.google.fr:1234", config), deadline,
-      NULL);
+      nullptr);
   GPR_ASSERT(c);
 
-  error = grpc_call_start_batch(c, op, 0, tag(1), NULL);
+  error = grpc_call_start_batch(c, op, 0, tag(1), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
   CQ_EXPECT_COMPLETION(cqv, tag(1), 1);
   cq_verify(cqv);
@@ -114,7 +114,7 @@ static void empty_batch_body(grpc_end2end_test_config config,
 static void test_invoke_empty_body(grpc_end2end_test_config config) {
   grpc_end2end_test_fixture f;
 
-  f = begin_test(config, "test_invoke_empty_body", NULL, NULL);
+  f = begin_test(config, "test_invoke_empty_body", nullptr, nullptr);
   empty_batch_body(config, f);
   end_test(&f);
   config.tear_down_data(&f);
diff --git a/test/core/end2end/tests/filter_call_init_fails.cc b/test/core/end2end/tests/filter_call_init_fails.cc
index ecf0cc3aca..6eed68a2f9 100644
--- a/test/core/end2end/tests/filter_call_init_fails.cc
+++ b/test/core/end2end/tests/filter_call_init_fails.cc
@@ -63,7 +63,7 @@ static gpr_timespec five_seconds_from_now(void) {
 static void drain_cq(grpc_completion_queue* cq) {
   grpc_event ev;
   do {
-    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), NULL);
+    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), nullptr);
   } while (ev.type != GRPC_QUEUE_SHUTDOWN);
 }
 
@@ -72,16 +72,16 @@ static void shutdown_server(grpc_end2end_test_fixture* f) {
   grpc_server_shutdown_and_notify(f->server, f->shutdown_cq, tag(1000));
   GPR_ASSERT(grpc_completion_queue_pluck(f->shutdown_cq, tag(1000),
                                          grpc_timeout_seconds_to_deadline(5),
-                                         NULL)
+                                         nullptr)
                  .type == GRPC_OP_COMPLETE);
   grpc_server_destroy(f->server);
-  f->server = NULL;
+  f->server = nullptr;
 }
 
 static void shutdown_client(grpc_end2end_test_fixture* f) {
   if (!f->client) return;
   grpc_channel_destroy(f->client);
-  f->client = NULL;
+  f->client = nullptr;
 }
 
 static void end_test(grpc_end2end_test_fixture* f) {
@@ -104,14 +104,14 @@ static void test_server_channel_filter(grpc_end2end_test_config config) {
   grpc_byte_buffer* request_payload =
       grpc_raw_byte_buffer_create(&request_payload_slice, 1);
   grpc_end2end_test_fixture f =
-      begin_test(config, "filter_call_init_fails", NULL, NULL);
+      begin_test(config, "filter_call_init_fails", nullptr, nullptr);
   cq_verifier* cqv = cq_verifier_create(f.cq);
   grpc_op ops[6];
   grpc_op* op;
   grpc_metadata_array initial_metadata_recv;
   grpc_metadata_array trailing_metadata_recv;
   grpc_metadata_array request_metadata_recv;
-  grpc_byte_buffer* request_payload_recv = NULL;
+  grpc_byte_buffer* request_payload_recv = nullptr;
   grpc_call_details call_details;
   grpc_status_code status;
   grpc_call_error error;
@@ -119,10 +119,10 @@ static void test_server_channel_filter(grpc_end2end_test_config config) {
 
   gpr_timespec deadline = five_seconds_from_now();
   c = grpc_channel_create_call(
-      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+      f.client, nullptr, GRPC_PROPAGATE_DEFAULTS, f.cq,
       grpc_slice_from_static_string("/foo"),
       get_host_override_slice("foo.test.google.fr:1234", config), deadline,
-      NULL);
+      nullptr);
   GPR_ASSERT(c);
 
   grpc_metadata_array_init(&initial_metadata_recv);
@@ -134,32 +134,32 @@ static void test_server_channel_filter(grpc_end2end_test_config config) {
   op = ops;
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
   op->data.send_initial_metadata.count = 0;
-  op->data.send_initial_metadata.metadata = NULL;
+  op->data.send_initial_metadata.metadata = nullptr;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_MESSAGE;
   op->data.send_message.send_message = request_payload;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_CLOSE_FROM_CLIENT;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_INITIAL_METADATA;
   op->data.recv_initial_metadata.recv_initial_metadata = &initial_metadata_recv;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_STATUS_ON_CLIENT;
   op->data.recv_status_on_client.trailing_metadata = &trailing_metadata_recv;
   op->data.recv_status_on_client.status = &status;
   op->data.recv_status_on_client.status_details = &details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), NULL);
+  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   error =
@@ -200,24 +200,24 @@ static void test_client_channel_filter(grpc_end2end_test_config config) {
       grpc_raw_byte_buffer_create(&request_payload_slice, 1);
   gpr_timespec deadline = five_seconds_from_now();
   grpc_end2end_test_fixture f =
-      begin_test(config, "filter_call_init_fails", NULL, NULL);
+      begin_test(config, "filter_call_init_fails", nullptr, nullptr);
   cq_verifier* cqv = cq_verifier_create(f.cq);
   grpc_op ops[6];
   grpc_op* op;
   grpc_metadata_array initial_metadata_recv;
   grpc_metadata_array trailing_metadata_recv;
   grpc_metadata_array request_metadata_recv;
-  grpc_byte_buffer* request_payload_recv = NULL;
+  grpc_byte_buffer* request_payload_recv = nullptr;
   grpc_call_details call_details;
   grpc_status_code status;
   grpc_call_error error;
   grpc_slice details;
 
   c = grpc_channel_create_call(
-      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+      f.client, nullptr, GRPC_PROPAGATE_DEFAULTS, f.cq,
       grpc_slice_from_static_string("/foo"),
       get_host_override_slice("foo.test.google.fr:1234", config), deadline,
-      NULL);
+      nullptr);
   GPR_ASSERT(c);
 
   grpc_metadata_array_init(&initial_metadata_recv);
@@ -229,32 +229,32 @@ static void test_client_channel_filter(grpc_end2end_test_config config) {
   op = ops;
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
   op->data.send_initial_metadata.count = 0;
-  op->data.send_initial_metadata.metadata = NULL;
+  op->data.send_initial_metadata.metadata = nullptr;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_MESSAGE;
   op->data.send_message.send_message = request_payload;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_CLOSE_FROM_CLIENT;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_INITIAL_METADATA;
   op->data.recv_initial_metadata.recv_initial_metadata = &initial_metadata_recv;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_STATUS_ON_CLIENT;
   op->data.recv_status_on_client.trailing_metadata = &trailing_metadata_recv;
   op->data.recv_status_on_client.status = &status;
   op->data.recv_status_on_client.status_details = &details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), NULL);
+  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   CQ_EXPECT_COMPLETION(cqv, tag(1), 1);
@@ -290,24 +290,24 @@ static void test_client_subchannel_filter(grpc_end2end_test_config config) {
       grpc_raw_byte_buffer_create(&request_payload_slice, 1);
   gpr_timespec deadline = five_seconds_from_now();
   grpc_end2end_test_fixture f =
-      begin_test(config, "filter_call_init_fails", NULL, NULL);
+      begin_test(config, "filter_call_init_fails", nullptr, nullptr);
   cq_verifier* cqv = cq_verifier_create(f.cq);
   grpc_op ops[6];
   grpc_op* op;
   grpc_metadata_array initial_metadata_recv;
   grpc_metadata_array trailing_metadata_recv;
   grpc_metadata_array request_metadata_recv;
-  grpc_byte_buffer* request_payload_recv = NULL;
+  grpc_byte_buffer* request_payload_recv = nullptr;
   grpc_call_details call_details;
   grpc_status_code status;
   grpc_call_error error;
   grpc_slice details;
 
   c = grpc_channel_create_call(
-      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+      f.client, nullptr, GRPC_PROPAGATE_DEFAULTS, f.cq,
       grpc_slice_from_static_string("/foo"),
       get_host_override_slice("foo.test.google.fr:1234", config), deadline,
-      NULL);
+      nullptr);
   GPR_ASSERT(c);
 
   grpc_metadata_array_init(&initial_metadata_recv);
@@ -319,33 +319,33 @@ static void test_client_subchannel_filter(grpc_end2end_test_config config) {
   op = ops;
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
   op->data.send_initial_metadata.count = 0;
-  op->data.send_initial_metadata.metadata = NULL;
+  op->data.send_initial_metadata.metadata = nullptr;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_MESSAGE;
   op->data.send_message.send_message = request_payload;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_CLOSE_FROM_CLIENT;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_INITIAL_METADATA;
   op->data.recv_initial_metadata.recv_initial_metadata = &initial_metadata_recv;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_STATUS_ON_CLIENT;
   op->data.recv_status_on_client.trailing_metadata = &trailing_metadata_recv;
   op->data.recv_status_on_client.status = &status;
   op->data.recv_status_on_client.status_details = &details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
 
-  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), NULL);
+  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   CQ_EXPECT_COMPLETION(cqv, tag(1), 1);
@@ -363,13 +363,13 @@ static void test_client_subchannel_filter(grpc_end2end_test_config config) {
   details = grpc_empty_slice();
 
   c = grpc_channel_create_call(
-      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+      f.client, nullptr, GRPC_PROPAGATE_DEFAULTS, f.cq,
       grpc_slice_from_static_string("/foo"),
       get_host_override_slice("foo.test.google.fr:1234", config), deadline,
-      NULL);
+      nullptr);
   GPR_ASSERT(c);
 
-  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(2), NULL);
+  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(2), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   CQ_EXPECT_COMPLETION(cqv, tag(2), 1);
@@ -449,7 +449,7 @@ static bool maybe_add_server_channel_filter(grpc_exec_ctx* exec_ctx,
         grpc_channel_stack_builder_create_iterator_at_last(builder);
     GPR_ASSERT(grpc_channel_stack_builder_move_prev(it));
     const bool retval = grpc_channel_stack_builder_add_filter_before(
-        it, &test_filter, NULL, NULL);
+        it, &test_filter, nullptr, nullptr);
     grpc_channel_stack_builder_iterator_destroy(it);
     return retval;
   } else {
@@ -469,7 +469,7 @@ static bool maybe_add_client_channel_filter(grpc_exec_ctx* exec_ctx,
         grpc_channel_stack_builder_create_iterator_at_last(builder);
     GPR_ASSERT(grpc_channel_stack_builder_move_prev(it));
     const bool retval = grpc_channel_stack_builder_add_filter_before(
-        it, &test_filter, NULL, NULL);
+        it, &test_filter, nullptr, nullptr);
     grpc_channel_stack_builder_iterator_destroy(it);
     return retval;
   } else {
@@ -488,7 +488,7 @@ static bool maybe_add_client_subchannel_filter(
         grpc_channel_stack_builder_create_iterator_at_last(builder);
     GPR_ASSERT(grpc_channel_stack_builder_move_prev(it));
     const bool retval = grpc_channel_stack_builder_add_filter_before(
-        it, &test_filter, NULL, NULL);
+        it, &test_filter, nullptr, nullptr);
     grpc_channel_stack_builder_iterator_destroy(it);
     return retval;
   } else {
@@ -498,13 +498,13 @@ static bool maybe_add_client_subchannel_filter(
 
 static void init_plugin(void) {
   grpc_channel_init_register_stage(GRPC_SERVER_CHANNEL, INT_MAX,
-                                   maybe_add_server_channel_filter, NULL);
+                                   maybe_add_server_channel_filter, nullptr);
   grpc_channel_init_register_stage(GRPC_CLIENT_CHANNEL, INT_MAX,
-                                   maybe_add_client_channel_filter, NULL);
+                                   maybe_add_client_channel_filter, nullptr);
   grpc_channel_init_register_stage(GRPC_CLIENT_SUBCHANNEL, INT_MAX,
-                                   maybe_add_client_subchannel_filter, NULL);
+                                   maybe_add_client_subchannel_filter, nullptr);
   grpc_channel_init_register_stage(GRPC_CLIENT_DIRECT_CHANNEL, INT_MAX,
-                                   maybe_add_client_channel_filter, NULL);
+                                   maybe_add_client_channel_filter, nullptr);
 }
 
 static void destroy_plugin(void) {}
diff --git a/test/core/end2end/tests/filter_causes_close.cc b/test/core/end2end/tests/filter_causes_close.cc
index b6cceabdd5..793f590686 100644
--- a/test/core/end2end/tests/filter_causes_close.cc
+++ b/test/core/end2end/tests/filter_causes_close.cc
@@ -58,7 +58,7 @@ static gpr_timespec five_seconds_from_now(void) {
 static void drain_cq(grpc_completion_queue* cq) {
   grpc_event ev;
   do {
-    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), NULL);
+    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), nullptr);
   } while (ev.type != GRPC_QUEUE_SHUTDOWN);
 }
 
@@ -67,16 +67,16 @@ static void shutdown_server(grpc_end2end_test_fixture* f) {
   grpc_server_shutdown_and_notify(f->server, f->shutdown_cq, tag(1000));
   GPR_ASSERT(grpc_completion_queue_pluck(f->shutdown_cq, tag(1000),
                                          grpc_timeout_seconds_to_deadline(5),
-                                         NULL)
+                                         nullptr)
                  .type == GRPC_OP_COMPLETE);
   grpc_server_destroy(f->server);
-  f->server = NULL;
+  f->server = nullptr;
 }
 
 static void shutdown_client(grpc_end2end_test_fixture* f) {
   if (!f->client) return;
   grpc_channel_destroy(f->client);
-  f->client = NULL;
+  f->client = nullptr;
 }
 
 static void end_test(grpc_end2end_test_fixture* f) {
@@ -98,14 +98,14 @@ static void test_request(grpc_end2end_test_config config) {
   grpc_byte_buffer* request_payload =
       grpc_raw_byte_buffer_create(&request_payload_slice, 1);
   grpc_end2end_test_fixture f =
-      begin_test(config, "filter_causes_close", NULL, NULL);
+      begin_test(config, "filter_causes_close", nullptr, nullptr);
   cq_verifier* cqv = cq_verifier_create(f.cq);
   grpc_op ops[6];
   grpc_op* op;
   grpc_metadata_array initial_metadata_recv;
   grpc_metadata_array trailing_metadata_recv;
   grpc_metadata_array request_metadata_recv;
-  grpc_byte_buffer* request_payload_recv = NULL;
+  grpc_byte_buffer* request_payload_recv = nullptr;
   grpc_call_details call_details;
   grpc_status_code status;
   grpc_call_error error;
@@ -113,10 +113,10 @@ static void test_request(grpc_end2end_test_config config) {
 
   gpr_timespec deadline = five_seconds_from_now();
   c = grpc_channel_create_call(
-      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+      f.client, nullptr, GRPC_PROPAGATE_DEFAULTS, f.cq,
       grpc_slice_from_static_string("/foo"),
       get_host_override_slice("foo.test.google.fr:1234", config), deadline,
-      NULL);
+      nullptr);
   GPR_ASSERT(c);
 
   grpc_metadata_array_init(&initial_metadata_recv);
@@ -128,32 +128,32 @@ static void test_request(grpc_end2end_test_config config) {
   op = ops;
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
   op->data.send_initial_metadata.count = 0;
-  op->data.send_initial_metadata.metadata = NULL;
+  op->data.send_initial_metadata.metadata = nullptr;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_MESSAGE;
   op->data.send_message.send_message = request_payload;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_CLOSE_FROM_CLIENT;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_INITIAL_METADATA;
   op->data.recv_initial_metadata.recv_initial_metadata = &initial_metadata_recv;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_STATUS_ON_CLIENT;
   op->data.recv_status_on_client.trailing_metadata = &trailing_metadata_recv;
   op->data.recv_status_on_client.status = &status;
   op->data.recv_status_on_client.status_details = &details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), NULL);
+  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   error =
@@ -262,7 +262,7 @@ static bool maybe_add_filter(grpc_exec_ctx* exec_ctx,
                              grpc_channel_stack_builder* builder, void* arg) {
   if (g_enable_filter) {
     return grpc_channel_stack_builder_prepend_filter(builder, &test_filter,
-                                                     NULL, NULL);
+                                                     nullptr, nullptr);
   } else {
     return true;
   }
@@ -270,7 +270,7 @@ static bool maybe_add_filter(grpc_exec_ctx* exec_ctx,
 
 static void init_plugin(void) {
   grpc_channel_init_register_stage(GRPC_SERVER_CHANNEL, 0, maybe_add_filter,
-                                   NULL);
+                                   nullptr);
 }
 
 static void destroy_plugin(void) {}
diff --git a/test/core/end2end/tests/filter_latency.cc b/test/core/end2end/tests/filter_latency.cc
index e8ec188ec3..07fee4c451 100644
--- a/test/core/end2end/tests/filter_latency.cc
+++ b/test/core/end2end/tests/filter_latency.cc
@@ -65,7 +65,7 @@ static gpr_timespec five_seconds_from_now(void) {
 static void drain_cq(grpc_completion_queue* cq) {
   grpc_event ev;
   do {
-    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), NULL);
+    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), nullptr);
   } while (ev.type != GRPC_QUEUE_SHUTDOWN);
 }
 
@@ -74,16 +74,16 @@ static void shutdown_server(grpc_end2end_test_fixture* f) {
   grpc_server_shutdown_and_notify(f->server, f->shutdown_cq, tag(1000));
   GPR_ASSERT(grpc_completion_queue_pluck(f->shutdown_cq, tag(1000),
                                          grpc_timeout_seconds_to_deadline(5),
-                                         NULL)
+                                         nullptr)
                  .type == GRPC_OP_COMPLETE);
   grpc_server_destroy(f->server);
-  f->server = NULL;
+  f->server = nullptr;
 }
 
 static void shutdown_client(grpc_end2end_test_fixture* f) {
   if (!f->client) return;
   grpc_channel_destroy(f->client);
-  f->client = NULL;
+  f->client = nullptr;
 }
 
 static void end_test(grpc_end2end_test_fixture* f) {
@@ -105,14 +105,14 @@ static void test_request(grpc_end2end_test_config config) {
   grpc_byte_buffer* request_payload =
       grpc_raw_byte_buffer_create(&request_payload_slice, 1);
   grpc_end2end_test_fixture f =
-      begin_test(config, "filter_latency", NULL, NULL);
+      begin_test(config, "filter_latency", nullptr, nullptr);
   cq_verifier* cqv = cq_verifier_create(f.cq);
   grpc_op ops[6];
   grpc_op* op;
   grpc_metadata_array initial_metadata_recv;
   grpc_metadata_array trailing_metadata_recv;
   grpc_metadata_array request_metadata_recv;
-  grpc_byte_buffer* request_payload_recv = NULL;
+  grpc_byte_buffer* request_payload_recv = nullptr;
   grpc_call_details call_details;
   grpc_status_code status;
   grpc_call_error error;
@@ -127,9 +127,9 @@ static void test_request(grpc_end2end_test_config config) {
 
   gpr_timespec deadline = five_seconds_from_now();
   c = grpc_channel_create_call(
-      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+      f.client, nullptr, GRPC_PROPAGATE_DEFAULTS, f.cq,
       grpc_slice_from_static_string("/foo"),
-      get_host_override_slice("foo.test.google.fr", config), deadline, NULL);
+      get_host_override_slice("foo.test.google.fr", config), deadline, nullptr);
   GPR_ASSERT(c);
 
   grpc_metadata_array_init(&initial_metadata_recv);
@@ -141,32 +141,32 @@ static void test_request(grpc_end2end_test_config config) {
   op = ops;
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
   op->data.send_initial_metadata.count = 0;
-  op->data.send_initial_metadata.metadata = NULL;
+  op->data.send_initial_metadata.metadata = nullptr;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_MESSAGE;
   op->data.send_message.send_message = request_payload;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_CLOSE_FROM_CLIENT;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_INITIAL_METADATA;
   op->data.recv_initial_metadata.recv_initial_metadata = &initial_metadata_recv;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_STATUS_ON_CLIENT;
   op->data.recv_status_on_client.trailing_metadata = &trailing_metadata_recv;
   op->data.recv_status_on_client.status = &status;
   op->data.recv_status_on_client.status_details = &details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), NULL);
+  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   error =
@@ -182,7 +182,7 @@ static void test_request(grpc_end2end_test_config config) {
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
   op->data.send_initial_metadata.count = 0;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_STATUS_FROM_SERVER;
   op->data.send_status_from_server.trailing_metadata_count = 0;
@@ -190,14 +190,14 @@ static void test_request(grpc_end2end_test_config config) {
   grpc_slice status_string = grpc_slice_from_static_string("xyz");
   op->data.send_status_from_server.status_details = &status_string;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_CLOSE_ON_SERVER;
   op->data.recv_close_on_server.cancelled = &was_cancelled;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(102), NULL);
+  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(102), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   CQ_EXPECT_COMPLETION(cqv, tag(102), 1);
@@ -322,7 +322,7 @@ static bool maybe_add_filter(grpc_exec_ctx* exec_ctx,
         grpc_channel_stack_builder_create_iterator_at_last(builder);
     GPR_ASSERT(grpc_channel_stack_builder_move_prev(it));
     const bool retval =
-        grpc_channel_stack_builder_add_filter_before(it, filter, NULL, NULL);
+        grpc_channel_stack_builder_add_filter_before(it, filter, nullptr, nullptr);
     grpc_channel_stack_builder_iterator_destroy(it);
     return retval;
   } else {
diff --git a/test/core/end2end/tests/graceful_server_shutdown.cc b/test/core/end2end/tests/graceful_server_shutdown.cc
index 22bdac4032..1c8acf37a4 100644
--- a/test/core/end2end/tests/graceful_server_shutdown.cc
+++ b/test/core/end2end/tests/graceful_server_shutdown.cc
@@ -53,20 +53,20 @@ static gpr_timespec five_seconds_from_now(void) {
 static void drain_cq(grpc_completion_queue* cq) {
   grpc_event ev;
   do {
-    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), NULL);
+    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), nullptr);
   } while (ev.type != GRPC_QUEUE_SHUTDOWN);
 }
 
 static void shutdown_server(grpc_end2end_test_fixture* f) {
   if (!f->server) return;
   grpc_server_destroy(f->server);
-  f->server = NULL;
+  f->server = nullptr;
 }
 
 static void shutdown_client(grpc_end2end_test_fixture* f) {
   if (!f->client) return;
   grpc_channel_destroy(f->client);
-  f->client = NULL;
+  f->client = nullptr;
 }
 
 static void end_test(grpc_end2end_test_fixture* f) {
@@ -85,7 +85,7 @@ static void test_early_server_shutdown_finishes_inflight_calls(
   grpc_call* c;
   grpc_call* s;
   grpc_end2end_test_fixture f = begin_test(
-      config, "test_early_server_shutdown_finishes_inflight_calls", NULL, NULL);
+      config, "test_early_server_shutdown_finishes_inflight_calls", nullptr, nullptr);
   cq_verifier* cqv = cq_verifier_create(f.cq);
   grpc_op ops[6];
   grpc_op* op;
@@ -100,10 +100,10 @@ static void test_early_server_shutdown_finishes_inflight_calls(
 
   gpr_timespec deadline = n_seconds_from_now(10);
   c = grpc_channel_create_call(
-      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+      f.client, nullptr, GRPC_PROPAGATE_DEFAULTS, f.cq,
       grpc_slice_from_static_string("/foo"),
       get_host_override_slice("foo.test.google.fr:1234", config), deadline,
-      NULL);
+      nullptr);
   GPR_ASSERT(c);
 
   grpc_metadata_array_init(&initial_metadata_recv);
@@ -115,27 +115,27 @@ static void test_early_server_shutdown_finishes_inflight_calls(
   op = ops;
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
   op->data.send_initial_metadata.count = 0;
-  op->data.send_initial_metadata.metadata = NULL;
+  op->data.send_initial_metadata.metadata = nullptr;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_CLOSE_FROM_CLIENT;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_INITIAL_METADATA;
   op->data.recv_initial_metadata.recv_initial_metadata = &initial_metadata_recv;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_STATUS_ON_CLIENT;
   op->data.recv_status_on_client.trailing_metadata = &trailing_metadata_recv;
   op->data.recv_status_on_client.status = &status;
   op->data.recv_status_on_client.status_details = &details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), NULL);
+  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   error =
@@ -154,7 +154,7 @@ static void test_early_server_shutdown_finishes_inflight_calls(
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
   op->data.send_initial_metadata.count = 0;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_STATUS_FROM_SERVER;
   op->data.send_status_from_server.trailing_metadata_count = 0;
@@ -162,14 +162,14 @@ static void test_early_server_shutdown_finishes_inflight_calls(
   grpc_slice status_details = grpc_slice_from_static_string("xyz");
   op->data.send_status_from_server.status_details = &status_details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_CLOSE_ON_SERVER;
   op->data.recv_close_on_server.cancelled = &was_cancelled;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(102), NULL);
+  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(102), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   CQ_EXPECT_COMPLETION(cqv, tag(102), 1);
diff --git a/test/core/end2end/tests/high_initial_seqno.cc b/test/core/end2end/tests/high_initial_seqno.cc
index 72f1d0fd3d..d390a954e5 100644
--- a/test/core/end2end/tests/high_initial_seqno.cc
+++ b/test/core/end2end/tests/high_initial_seqno.cc
@@ -57,7 +57,7 @@ static gpr_timespec five_seconds_from_now(void) {
 static void drain_cq(grpc_completion_queue* cq) {
   grpc_event ev;
   do {
-    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), NULL);
+    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), nullptr);
   } while (ev.type != GRPC_QUEUE_SHUTDOWN);
 }
 
@@ -66,16 +66,16 @@ static void shutdown_server(grpc_end2end_test_fixture* f) {
   grpc_server_shutdown_and_notify(f->server, f->shutdown_cq, tag(1000));
   GPR_ASSERT(grpc_completion_queue_pluck(f->shutdown_cq, tag(1000),
                                          grpc_timeout_seconds_to_deadline(5),
-                                         NULL)
+                                         nullptr)
                  .type == GRPC_OP_COMPLETE);
   grpc_server_destroy(f->server);
-  f->server = NULL;
+  f->server = nullptr;
 }
 
 static void shutdown_client(grpc_end2end_test_fixture* f) {
   if (!f->client) return;
   grpc_channel_destroy(f->client);
-  f->client = NULL;
+  f->client = nullptr;
 }
 
 static void end_test(grpc_end2end_test_fixture* f) {
@@ -106,10 +106,10 @@ static void simple_request_body(grpc_end2end_test_config config,
 
   gpr_timespec deadline = five_seconds_from_now();
   c = grpc_channel_create_call(
-      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+      f.client, nullptr, GRPC_PROPAGATE_DEFAULTS, f.cq,
       grpc_slice_from_static_string("/foo"),
       get_host_override_slice("foo.test.google.fr:1234", config), deadline,
-      NULL);
+      nullptr);
   GPR_ASSERT(c);
 
   grpc_metadata_array_init(&initial_metadata_recv);
@@ -122,25 +122,25 @@ static void simple_request_body(grpc_end2end_test_config config,
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
   op->data.send_initial_metadata.count = 0;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_CLOSE_FROM_CLIENT;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_INITIAL_METADATA;
   op->data.recv_initial_metadata.recv_initial_metadata = &initial_metadata_recv;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_STATUS_ON_CLIENT;
   op->data.recv_status_on_client.trailing_metadata = &trailing_metadata_recv;
   op->data.recv_status_on_client.status = &status;
   op->data.recv_status_on_client.status_details = &details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), NULL);
+  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   error =
@@ -155,7 +155,7 @@ static void simple_request_body(grpc_end2end_test_config config,
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
   op->data.send_initial_metadata.count = 0;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_STATUS_FROM_SERVER;
   op->data.send_status_from_server.trailing_metadata_count = 0;
@@ -163,14 +163,14 @@ static void simple_request_body(grpc_end2end_test_config config,
   grpc_slice status_details = grpc_slice_from_static_string("xyz");
   op->data.send_status_from_server.status_details = &status_details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_CLOSE_ON_SERVER;
   op->data.recv_close_on_server.cancelled = &was_cancelled;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(102), NULL);
+  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(102), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   CQ_EXPECT_COMPLETION(cqv, tag(102), 1);
@@ -219,7 +219,7 @@ static void test_invoke_10_simple_requests(grpc_end2end_test_config config,
 
   gpr_asprintf(&name, "test_invoke_requests first_seqno=%d",
                initial_sequence_number);
-  f = begin_test(config, name, &client_args, NULL);
+  f = begin_test(config, name, &client_args, nullptr);
   for (i = 0; i < 10; i++) {
     simple_request_body(config, f);
     gpr_log(GPR_INFO, "Running test: Passed simple request %d", i);
diff --git a/test/core/end2end/tests/hpack_size.cc b/test/core/end2end/tests/hpack_size.cc
index b2c683ec8e..7ac5fefa22 100644
--- a/test/core/end2end/tests/hpack_size.cc
+++ b/test/core/end2end/tests/hpack_size.cc
@@ -197,7 +197,7 @@ static gpr_timespec five_seconds_from_now(void) {
 static void drain_cq(grpc_completion_queue* cq) {
   grpc_event ev;
   do {
-    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), NULL);
+    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), nullptr);
   } while (ev.type != GRPC_QUEUE_SHUTDOWN);
 }
 
@@ -206,16 +206,16 @@ static void shutdown_server(grpc_end2end_test_fixture* f) {
   grpc_server_shutdown_and_notify(f->server, f->shutdown_cq, tag(1000));
   GPR_ASSERT(grpc_completion_queue_pluck(f->shutdown_cq, tag(1000),
                                          grpc_timeout_seconds_to_deadline(5),
-                                         NULL)
+                                         nullptr)
                  .type == GRPC_OP_COMPLETE);
   grpc_server_destroy(f->server);
-  f->server = NULL;
+  f->server = nullptr;
 }
 
 static void shutdown_client(grpc_end2end_test_fixture* f) {
   if (!f->client) return;
   grpc_channel_destroy(f->client);
-  f->client = NULL;
+  f->client = nullptr;
 }
 
 static void end_test(grpc_end2end_test_fixture* f) {
@@ -258,10 +258,10 @@ static void simple_request_body(grpc_end2end_test_config config,
 
   gpr_timespec deadline = five_seconds_from_now();
   c = grpc_channel_create_call(
-      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+      f.client, nullptr, GRPC_PROPAGATE_DEFAULTS, f.cq,
       grpc_slice_from_static_string("/foo"),
       get_host_override_slice("foo.test.google.fr:1234", config), deadline,
-      NULL);
+      nullptr);
   GPR_ASSERT(c);
 
   grpc_metadata_array_init(&initial_metadata_recv);
@@ -275,25 +275,25 @@ static void simple_request_body(grpc_end2end_test_config config,
   op->data.send_initial_metadata.count = GPR_ARRAY_SIZE(extra_metadata);
   op->data.send_initial_metadata.metadata = extra_metadata;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_CLOSE_FROM_CLIENT;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_INITIAL_METADATA;
   op->data.recv_initial_metadata.recv_initial_metadata = &initial_metadata_recv;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_STATUS_ON_CLIENT;
   op->data.recv_status_on_client.trailing_metadata = &trailing_metadata_recv;
   op->data.recv_status_on_client.status = &status;
   op->data.recv_status_on_client.status_details = &details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), NULL);
+  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   error =
@@ -308,7 +308,7 @@ static void simple_request_body(grpc_end2end_test_config config,
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
   op->data.send_initial_metadata.count = 0;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_STATUS_FROM_SERVER;
   op->data.send_status_from_server.trailing_metadata_count = 0;
@@ -316,14 +316,14 @@ static void simple_request_body(grpc_end2end_test_config config,
   grpc_slice status_details = grpc_slice_from_static_string("xyz");
   op->data.send_status_from_server.status_details = &status_details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_CLOSE_ON_SERVER;
   op->data.recv_close_on_server.cancelled = &was_cancelled;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(102), NULL);
+  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(102), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   CQ_EXPECT_COMPLETION(cqv, tag(102), 1);
@@ -372,8 +372,8 @@ static void test_size(grpc_end2end_test_config config, int encode_size,
   client_args.args = &client_arg;
 
   gpr_asprintf(&name, "test_size:e=%d:d=%d", encode_size, decode_size);
-  f = begin_test(config, name, encode_size != 4096 ? &client_args : NULL,
-                 decode_size != 4096 ? &server_args : NULL);
+  f = begin_test(config, name, encode_size != 4096 ? &client_args : nullptr,
+                 decode_size != 4096 ? &server_args : nullptr);
   for (i = 0; i < 4 * GPR_ARRAY_SIZE(hobbits); i++) {
     simple_request_body(config, f, i);
   }
diff --git a/test/core/end2end/tests/idempotent_request.cc b/test/core/end2end/tests/idempotent_request.cc
index 4f61caa6df..e39975382a 100644
--- a/test/core/end2end/tests/idempotent_request.cc
+++ b/test/core/end2end/tests/idempotent_request.cc
@@ -55,7 +55,7 @@ static gpr_timespec five_seconds_from_now(void) {
 static void drain_cq(grpc_completion_queue* cq) {
   grpc_event ev;
   do {
-    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), NULL);
+    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), nullptr);
   } while (ev.type != GRPC_QUEUE_SHUTDOWN);
 }
 
@@ -64,16 +64,16 @@ static void shutdown_server(grpc_end2end_test_fixture* f) {
   grpc_server_shutdown_and_notify(f->server, f->shutdown_cq, tag(1000));
   GPR_ASSERT(grpc_completion_queue_pluck(f->shutdown_cq, tag(1000),
                                          grpc_timeout_seconds_to_deadline(5),
-                                         NULL)
+                                         nullptr)
                  .type == GRPC_OP_COMPLETE);
   grpc_server_destroy(f->server);
-  f->server = NULL;
+  f->server = nullptr;
 }
 
 static void shutdown_client(grpc_end2end_test_fixture* f) {
   if (!f->client) return;
   grpc_channel_destroy(f->client);
-  f->client = NULL;
+  f->client = nullptr;
 }
 
 static void end_test(grpc_end2end_test_fixture* f) {
@@ -105,14 +105,14 @@ static void simple_request_body(grpc_end2end_test_config config,
 
   gpr_timespec deadline = five_seconds_from_now();
   c = grpc_channel_create_call(
-      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+      f.client, nullptr, GRPC_PROPAGATE_DEFAULTS, f.cq,
       grpc_slice_from_static_string("/foo"),
       get_host_override_slice("foo.test.google.fr:1234", config), deadline,
-      NULL);
+      nullptr);
   GPR_ASSERT(c);
 
   peer = grpc_call_get_peer(c);
-  GPR_ASSERT(peer != NULL);
+  GPR_ASSERT(peer != nullptr);
   gpr_log(GPR_DEBUG, "client_peer_before_call=%s", peer);
   gpr_free(peer);
 
@@ -126,25 +126,25 @@ static void simple_request_body(grpc_end2end_test_config config,
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
   op->data.send_initial_metadata.count = 0;
   op->flags = GRPC_INITIAL_METADATA_IDEMPOTENT_REQUEST;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_CLOSE_FROM_CLIENT;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_INITIAL_METADATA;
   op->data.recv_initial_metadata.recv_initial_metadata = &initial_metadata_recv;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_STATUS_ON_CLIENT;
   op->data.recv_status_on_client.trailing_metadata = &trailing_metadata_recv;
   op->data.recv_status_on_client.status = &status;
   op->data.recv_status_on_client.status_details = &details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), NULL);
+  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   error =
@@ -155,11 +155,11 @@ static void simple_request_body(grpc_end2end_test_config config,
   cq_verify(cqv);
 
   peer = grpc_call_get_peer(s);
-  GPR_ASSERT(peer != NULL);
+  GPR_ASSERT(peer != nullptr);
   gpr_log(GPR_DEBUG, "server_peer=%s", peer);
   gpr_free(peer);
   peer = grpc_call_get_peer(c);
-  GPR_ASSERT(peer != NULL);
+  GPR_ASSERT(peer != nullptr);
   gpr_log(GPR_DEBUG, "client_peer=%s", peer);
   gpr_free(peer);
 
@@ -168,7 +168,7 @@ static void simple_request_body(grpc_end2end_test_config config,
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
   op->data.send_initial_metadata.count = 0;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_STATUS_FROM_SERVER;
   op->data.send_status_from_server.trailing_metadata_count = 0;
@@ -176,14 +176,14 @@ static void simple_request_body(grpc_end2end_test_config config,
   grpc_slice status_details = grpc_slice_from_static_string("xyz");
   op->data.send_status_from_server.status_details = &status_details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_CLOSE_ON_SERVER;
   op->data.recv_close_on_server.cancelled = &was_cancelled;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(102), NULL);
+  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(102), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   CQ_EXPECT_COMPLETION(cqv, tag(102), 1);
@@ -213,7 +213,7 @@ static void simple_request_body(grpc_end2end_test_config config,
 static void test_invoke_simple_request(grpc_end2end_test_config config) {
   grpc_end2end_test_fixture f;
 
-  f = begin_test(config, "test_invoke_simple_request", NULL, NULL);
+  f = begin_test(config, "test_invoke_simple_request", nullptr, nullptr);
   simple_request_body(config, f);
   end_test(&f);
   config.tear_down_data(&f);
@@ -222,7 +222,7 @@ static void test_invoke_simple_request(grpc_end2end_test_config config) {
 static void test_invoke_10_simple_requests(grpc_end2end_test_config config) {
   int i;
   grpc_end2end_test_fixture f =
-      begin_test(config, "test_invoke_10_simple_requests", NULL, NULL);
+      begin_test(config, "test_invoke_10_simple_requests", nullptr, nullptr);
   for (i = 0; i < 10; i++) {
     simple_request_body(config, f);
     gpr_log(GPR_INFO, "Passed simple request %d", i);
diff --git a/test/core/end2end/tests/invoke_large_request.cc b/test/core/end2end/tests/invoke_large_request.cc
index ade61ac91d..8a67e3c2b1 100644
--- a/test/core/end2end/tests/invoke_large_request.cc
+++ b/test/core/end2end/tests/invoke_large_request.cc
@@ -50,7 +50,7 @@ static gpr_timespec n_seconds_from_now(int n) {
 static void drain_cq(grpc_completion_queue* cq) {
   grpc_event ev;
   do {
-    ev = grpc_completion_queue_next(cq, n_seconds_from_now(5), NULL);
+    ev = grpc_completion_queue_next(cq, n_seconds_from_now(5), nullptr);
   } while (ev.type != GRPC_QUEUE_SHUTDOWN);
 }
 
@@ -59,16 +59,16 @@ static void shutdown_server(grpc_end2end_test_fixture* f) {
   grpc_server_shutdown_and_notify(f->server, f->shutdown_cq, tag(1000));
   GPR_ASSERT(grpc_completion_queue_pluck(f->shutdown_cq, tag(1000),
                                          grpc_timeout_seconds_to_deadline(5),
-                                         NULL)
+                                         nullptr)
                  .type == GRPC_OP_COMPLETE);
   grpc_server_destroy(f->server);
-  f->server = NULL;
+  f->server = nullptr;
 }
 
 static void shutdown_client(grpc_end2end_test_fixture* f) {
   if (!f->client) return;
   grpc_channel_destroy(f->client);
-  f->client = NULL;
+  f->client = nullptr;
 }
 
 static void end_test(grpc_end2end_test_fixture* f) {
@@ -121,8 +121,8 @@ static void test_invoke_large_request(grpc_end2end_test_config config,
   grpc_metadata_array initial_metadata_recv;
   grpc_metadata_array trailing_metadata_recv;
   grpc_metadata_array request_metadata_recv;
-  grpc_byte_buffer* request_payload_recv = NULL;
-  grpc_byte_buffer* response_payload_recv = NULL;
+  grpc_byte_buffer* request_payload_recv = nullptr;
+  grpc_byte_buffer* response_payload_recv = nullptr;
   grpc_call_details call_details;
   grpc_status_code status;
   grpc_call_error error;
@@ -131,10 +131,10 @@ static void test_invoke_large_request(grpc_end2end_test_config config,
 
   gpr_timespec deadline = n_seconds_from_now(30);
   c = grpc_channel_create_call(
-      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+      f.client, nullptr, GRPC_PROPAGATE_DEFAULTS, f.cq,
       grpc_slice_from_static_string("/foo"),
       get_host_override_slice("foo.test.google.fr:1234", config), deadline,
-      NULL);
+      nullptr);
   GPR_ASSERT(c);
 
   grpc_metadata_array_init(&initial_metadata_recv);
@@ -147,35 +147,35 @@ static void test_invoke_large_request(grpc_end2end_test_config config,
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
   op->data.send_initial_metadata.count = 0;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_MESSAGE;
   op->data.send_message.send_message = request_payload;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_CLOSE_FROM_CLIENT;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_INITIAL_METADATA;
   op->data.recv_initial_metadata.recv_initial_metadata = &initial_metadata_recv;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_MESSAGE;
   op->data.recv_message.recv_message = &response_payload_recv;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_STATUS_ON_CLIENT;
   op->data.recv_status_on_client.trailing_metadata = &trailing_metadata_recv;
   op->data.recv_status_on_client.status = &status;
   op->data.recv_status_on_client.status_details = &details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), NULL);
+  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   error =
@@ -190,14 +190,14 @@ static void test_invoke_large_request(grpc_end2end_test_config config,
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
   op->data.send_initial_metadata.count = 0;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_MESSAGE;
   op->data.recv_message.recv_message = &request_payload_recv;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(102), NULL);
+  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(102), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   CQ_EXPECT_COMPLETION(cqv, tag(102), 1);
@@ -208,12 +208,12 @@ static void test_invoke_large_request(grpc_end2end_test_config config,
   op->op = GRPC_OP_RECV_CLOSE_ON_SERVER;
   op->data.recv_close_on_server.cancelled = &was_cancelled;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_MESSAGE;
   op->data.send_message.send_message = response_payload;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_STATUS_FROM_SERVER;
   op->data.send_status_from_server.trailing_metadata_count = 0;
@@ -221,9 +221,9 @@ static void test_invoke_large_request(grpc_end2end_test_config config,
   grpc_slice status_details = grpc_slice_from_static_string("xyz");
   op->data.send_status_from_server.status_details = &status_details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(103), NULL);
+  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(103), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   CQ_EXPECT_COMPLETION(cqv, tag(103), 1);
diff --git a/test/core/end2end/tests/keepalive_timeout.cc b/test/core/end2end/tests/keepalive_timeout.cc
index d071254a98..822565510f 100644
--- a/test/core/end2end/tests/keepalive_timeout.cc
+++ b/test/core/end2end/tests/keepalive_timeout.cc
@@ -57,7 +57,7 @@ static gpr_timespec five_seconds_from_now(void) {
 static void drain_cq(grpc_completion_queue* cq) {
   grpc_event ev;
   do {
-    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), NULL);
+    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), nullptr);
   } while (ev.type != GRPC_QUEUE_SHUTDOWN);
 }
 
@@ -66,16 +66,16 @@ static void shutdown_server(grpc_end2end_test_fixture* f) {
 
   grpc_server_shutdown_and_notify(f->server, f->shutdown_cq, tag(1000));
   GPR_ASSERT(grpc_completion_queue_pluck(f->shutdown_cq, tag(1000),
-                                         five_seconds_from_now(), NULL)
+                                         five_seconds_from_now(), nullptr)
                  .type == GRPC_OP_COMPLETE);
   grpc_server_destroy(f->server);
-  f->server = NULL;
+  f->server = nullptr;
 }
 
 static void shutdown_client(grpc_end2end_test_fixture* f) {
   if (!f->client) return;
   grpc_channel_destroy(f->client);
-  f->client = NULL;
+  f->client = nullptr;
 }
 
 static void end_test(grpc_end2end_test_fixture* f) {
@@ -112,14 +112,14 @@ static void test_keepalive_timeout(grpc_end2end_test_config config) {
                                       keepalive_arg_elems};
 
   grpc_end2end_test_fixture f =
-      begin_test(config, "keepalive_timeout", &keepalive_args, NULL);
+      begin_test(config, "keepalive_timeout", &keepalive_args, nullptr);
   cq_verifier* cqv = cq_verifier_create(f.cq);
   grpc_op ops[6];
   grpc_op* op;
   grpc_metadata_array initial_metadata_recv;
   grpc_metadata_array trailing_metadata_recv;
   grpc_metadata_array request_metadata_recv;
-  grpc_byte_buffer* response_payload_recv = NULL;
+  grpc_byte_buffer* response_payload_recv = nullptr;
   grpc_call_details call_details;
   grpc_status_code status;
   grpc_call_error error;
@@ -130,10 +130,10 @@ static void test_keepalive_timeout(grpc_end2end_test_config config) {
 
   gpr_timespec deadline = five_seconds_from_now();
   c = grpc_channel_create_call(
-      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+      f.client, nullptr, GRPC_PROPAGATE_DEFAULTS, f.cq,
       grpc_slice_from_static_string("/foo"),
       get_host_override_slice("foo.test.google.fr:1234", config), deadline,
-      NULL);
+      nullptr);
   GPR_ASSERT(c);
 
   grpc_metadata_array_init(&initial_metadata_recv);
@@ -154,7 +154,7 @@ static void test_keepalive_timeout(grpc_end2end_test_config config) {
   op->op = GRPC_OP_RECV_MESSAGE;
   op->data.recv_message.recv_message = &response_payload_recv;
   op++;
-  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), NULL);
+  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   GPR_ASSERT(GRPC_CALL_OK == grpc_server_request_call(
@@ -171,7 +171,7 @@ static void test_keepalive_timeout(grpc_end2end_test_config config) {
   op->op = GRPC_OP_SEND_MESSAGE;
   op->data.send_message.send_message = response_payload;
   op++;
-  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(102), NULL);
+  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(102), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   CQ_EXPECT_COMPLETION(cqv, tag(102), 1);
@@ -185,7 +185,7 @@ static void test_keepalive_timeout(grpc_end2end_test_config config) {
   op->data.recv_status_on_client.status = &status;
   op->data.recv_status_on_client.status_details = &details;
   op++;
-  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(3), NULL);
+  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(3), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   CQ_EXPECT_COMPLETION(cqv, tag(3), 1);
diff --git a/test/core/end2end/tests/large_metadata.cc b/test/core/end2end/tests/large_metadata.cc
index 4afd9f31ba..8ddf433ac0 100644
--- a/test/core/end2end/tests/large_metadata.cc
+++ b/test/core/end2end/tests/large_metadata.cc
@@ -53,7 +53,7 @@ static gpr_timespec five_seconds_from_now(void) {
 static void drain_cq(grpc_completion_queue* cq) {
   grpc_event ev;
   do {
-    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), NULL);
+    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), nullptr);
   } while (ev.type != GRPC_QUEUE_SHUTDOWN);
 }
 
@@ -62,16 +62,16 @@ static void shutdown_server(grpc_end2end_test_fixture* f) {
   grpc_server_shutdown_and_notify(f->server, f->shutdown_cq, tag(1000));
   GPR_ASSERT(grpc_completion_queue_pluck(f->shutdown_cq, tag(1000),
                                          grpc_timeout_seconds_to_deadline(5),
-                                         NULL)
+                                         nullptr)
                  .type == GRPC_OP_COMPLETE);
   grpc_server_destroy(f->server);
-  f->server = NULL;
+  f->server = nullptr;
 }
 
 static void shutdown_client(grpc_end2end_test_fixture* f) {
   if (!f->client) return;
   grpc_channel_destroy(f->client);
-  f->client = NULL;
+  f->client = nullptr;
 }
 
 static void end_test(grpc_end2end_test_fixture* f) {
@@ -107,7 +107,7 @@ static void test_request_with_large_metadata(grpc_end2end_test_config config) {
   grpc_metadata_array initial_metadata_recv;
   grpc_metadata_array trailing_metadata_recv;
   grpc_metadata_array request_metadata_recv;
-  grpc_byte_buffer* request_payload_recv = NULL;
+  grpc_byte_buffer* request_payload_recv = nullptr;
   grpc_call_details call_details;
   grpc_status_code status;
   grpc_call_error error;
@@ -116,10 +116,10 @@ static void test_request_with_large_metadata(grpc_end2end_test_config config) {
 
   gpr_timespec deadline = five_seconds_from_now();
   c = grpc_channel_create_call(
-      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+      f.client, nullptr, GRPC_PROPAGATE_DEFAULTS, f.cq,
       grpc_slice_from_static_string("/foo"),
       get_host_override_slice("foo.test.google.fr:1234", config), deadline,
-      NULL);
+      nullptr);
   GPR_ASSERT(c);
 
   meta.key = grpc_slice_from_static_string("key");
@@ -138,30 +138,30 @@ static void test_request_with_large_metadata(grpc_end2end_test_config config) {
   op->data.send_initial_metadata.count = 1;
   op->data.send_initial_metadata.metadata = &meta;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_MESSAGE;
   op->data.send_message.send_message = request_payload;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_CLOSE_FROM_CLIENT;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_INITIAL_METADATA;
   op->data.recv_initial_metadata.recv_initial_metadata = &initial_metadata_recv;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_STATUS_ON_CLIENT;
   op->data.recv_status_on_client.trailing_metadata = &trailing_metadata_recv;
   op->data.recv_status_on_client.status = &status;
   op->data.recv_status_on_client.status_details = &details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), NULL);
+  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   error =
@@ -178,14 +178,14 @@ static void test_request_with_large_metadata(grpc_end2end_test_config config) {
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
   op->data.send_initial_metadata.count = 0;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_MESSAGE;
   op->data.recv_message.recv_message = &request_payload_recv;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(102), NULL);
+  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(102), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   CQ_EXPECT_COMPLETION(cqv, tag(102), 1);
@@ -198,7 +198,7 @@ static void test_request_with_large_metadata(grpc_end2end_test_config config) {
   op->op = GRPC_OP_RECV_CLOSE_ON_SERVER;
   op->data.recv_close_on_server.cancelled = &was_cancelled;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_STATUS_FROM_SERVER;
   op->data.send_status_from_server.trailing_metadata_count = 0;
@@ -206,9 +206,9 @@ static void test_request_with_large_metadata(grpc_end2end_test_config config) {
   grpc_slice status_details = grpc_slice_from_static_string("xyz");
   op->data.send_status_from_server.status_details = &status_details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(103), NULL);
+  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(103), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   CQ_EXPECT_COMPLETION(cqv, tag(103), 1);
diff --git a/test/core/end2end/tests/load_reporting_hook.cc b/test/core/end2end/tests/load_reporting_hook.cc
index 5c2c3b497c..faabec34cb 100644
--- a/test/core/end2end/tests/load_reporting_hook.cc
+++ b/test/core/end2end/tests/load_reporting_hook.cc
@@ -80,7 +80,7 @@ static gpr_timespec five_seconds_from_now(void) {
 static void drain_cq(grpc_completion_queue* cq) {
   grpc_event ev;
   do {
-    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), NULL);
+    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), nullptr);
   } while (ev.type != GRPC_QUEUE_SHUTDOWN);
 }
 
@@ -89,16 +89,16 @@ static void shutdown_server(grpc_end2end_test_fixture* f) {
   grpc_server_shutdown_and_notify(f->server, f->shutdown_cq, tag(1000));
   GPR_ASSERT(grpc_completion_queue_pluck(f->shutdown_cq, tag(1000),
                                          grpc_timeout_seconds_to_deadline(5),
-                                         NULL)
+                                         nullptr)
                  .type == GRPC_OP_COMPLETE);
   grpc_server_destroy(f->server);
-  f->server = NULL;
+  f->server = nullptr;
 }
 
 static void shutdown_client(grpc_end2end_test_fixture* f) {
   if (!f->client) return;
   grpc_channel_destroy(f->client);
-  f->client = NULL;
+  f->client = nullptr;
 }
 
 static void end_test(grpc_end2end_test_fixture* f) {
@@ -130,8 +130,8 @@ static void request_response_with_payload(
   grpc_metadata_array initial_metadata_recv;
   grpc_metadata_array trailing_metadata_recv;
   grpc_metadata_array request_metadata_recv;
-  grpc_byte_buffer* request_payload_recv = NULL;
-  grpc_byte_buffer* response_payload_recv = NULL;
+  grpc_byte_buffer* request_payload_recv = nullptr;
+  grpc_byte_buffer* response_payload_recv = nullptr;
   grpc_call_details call_details;
   grpc_status_code status;
   grpc_call_error error;
@@ -140,10 +140,10 @@ static void request_response_with_payload(
 
   gpr_timespec deadline = five_seconds_from_now();
   c = grpc_channel_create_call(
-      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+      f.client, nullptr, GRPC_PROPAGATE_DEFAULTS, f.cq,
       grpc_slice_from_static_string(method_name),
       get_host_override_slice("foo.test.google.fr:1234", config), deadline,
-      NULL);
+      nullptr);
   GPR_ASSERT(c);
 
   grpc_metadata_array_init(&initial_metadata_recv);
@@ -154,39 +154,39 @@ static void request_response_with_payload(
   memset(ops, 0, sizeof(ops));
   op = ops;
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
-  GPR_ASSERT(initial_lr_metadata != NULL);
+  GPR_ASSERT(initial_lr_metadata != nullptr);
   op->data.send_initial_metadata.count = 1;
   op->data.send_initial_metadata.metadata = initial_lr_metadata;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_MESSAGE;
   op->data.send_message.send_message = request_payload;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_CLOSE_FROM_CLIENT;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_INITIAL_METADATA;
   op->data.recv_initial_metadata.recv_initial_metadata = &initial_metadata_recv;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_MESSAGE;
   op->data.recv_message.recv_message = &response_payload_recv;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_STATUS_ON_CLIENT;
   op->data.recv_status_on_client.trailing_metadata = &trailing_metadata_recv;
   op->data.recv_status_on_client.status = &status;
   op->data.recv_status_on_client.status_details = &details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), NULL);
+  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   error =
@@ -201,14 +201,14 @@ static void request_response_with_payload(
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
   op->data.send_initial_metadata.count = 0;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_MESSAGE;
   op->data.recv_message.recv_message = &request_payload_recv;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(102), NULL);
+  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(102), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   CQ_EXPECT_COMPLETION(cqv, tag(102), 1);
@@ -219,24 +219,24 @@ static void request_response_with_payload(
   op->op = GRPC_OP_RECV_CLOSE_ON_SERVER;
   op->data.recv_close_on_server.cancelled = &was_cancelled;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_MESSAGE;
   op->data.send_message.send_message = response_payload;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_STATUS_FROM_SERVER;
-  GPR_ASSERT(trailing_lr_metadata != NULL);
+  GPR_ASSERT(trailing_lr_metadata != nullptr);
   op->data.send_status_from_server.trailing_metadata_count = 1;
   op->data.send_status_from_server.trailing_metadata = trailing_lr_metadata;
   op->data.send_status_from_server.status = GRPC_STATUS_OK;
   grpc_slice status_details = grpc_slice_from_static_string("xyz");
   op->data.send_status_from_server.status_details = &status_details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(103), NULL);
+  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(103), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   CQ_EXPECT_COMPLETION(cqv, tag(103), 1);
@@ -273,10 +273,10 @@ static void test_load_reporting_hook(grpc_end2end_test_config config) {
   /* Introduce load reporting for the server through its arguments */
   grpc_arg arg = grpc_load_reporting_enable_arg();
   grpc_channel_args* lr_server_args =
-      grpc_channel_args_copy_and_add(NULL, &arg, 1);
+      grpc_channel_args_copy_and_add(nullptr, &arg, 1);
 
   grpc_end2end_test_fixture f =
-      begin_test(config, "test_load_reporting_hook", NULL, lr_server_args);
+      begin_test(config, "test_load_reporting_hook", nullptr, lr_server_args);
 
   const char* method_name = "/gRPCFTW";
   const char* request_msg = "the msg from the client";
diff --git a/test/core/end2end/tests/max_concurrent_streams.cc b/test/core/end2end/tests/max_concurrent_streams.cc
index b8b49d65fb..c0539739e1 100644
--- a/test/core/end2end/tests/max_concurrent_streams.cc
+++ b/test/core/end2end/tests/max_concurrent_streams.cc
@@ -53,7 +53,7 @@ static gpr_timespec five_seconds_from_now(void) {
 static void drain_cq(grpc_completion_queue* cq) {
   grpc_event ev;
   do {
-    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), NULL);
+    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), nullptr);
   } while (ev.type != GRPC_QUEUE_SHUTDOWN);
 }
 
@@ -62,16 +62,16 @@ static void shutdown_server(grpc_end2end_test_fixture* f) {
   grpc_server_shutdown_and_notify(f->server, f->shutdown_cq, tag(1000));
   GPR_ASSERT(grpc_completion_queue_pluck(f->shutdown_cq, tag(1000),
                                          grpc_timeout_seconds_to_deadline(5),
-                                         NULL)
+                                         nullptr)
                  .type == GRPC_OP_COMPLETE);
   grpc_server_destroy(f->server);
-  f->server = NULL;
+  f->server = nullptr;
 }
 
 static void shutdown_client(grpc_end2end_test_fixture* f) {
   if (!f->client) return;
   grpc_channel_destroy(f->client);
-  f->client = NULL;
+  f->client = nullptr;
 }
 
 static void end_test(grpc_end2end_test_fixture* f) {
@@ -102,10 +102,10 @@ static void simple_request_body(grpc_end2end_test_config config,
 
   gpr_timespec deadline = five_seconds_from_now();
   c = grpc_channel_create_call(
-      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+      f.client, nullptr, GRPC_PROPAGATE_DEFAULTS, f.cq,
       grpc_slice_from_static_string("/foo"),
       get_host_override_slice("foo.test.google.fr:1234", config), deadline,
-      NULL);
+      nullptr);
   GPR_ASSERT(c);
 
   grpc_metadata_array_init(&initial_metadata_recv);
@@ -118,25 +118,25 @@ static void simple_request_body(grpc_end2end_test_config config,
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
   op->data.send_initial_metadata.count = 0;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_CLOSE_FROM_CLIENT;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_INITIAL_METADATA;
   op->data.recv_initial_metadata.recv_initial_metadata = &initial_metadata_recv;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_STATUS_ON_CLIENT;
   op->data.recv_status_on_client.trailing_metadata = &trailing_metadata_recv;
   op->data.recv_status_on_client.status = &status;
   op->data.recv_status_on_client.status_details = &details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), NULL);
+  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   error =
@@ -151,7 +151,7 @@ static void simple_request_body(grpc_end2end_test_config config,
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
   op->data.send_initial_metadata.count = 0;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_STATUS_FROM_SERVER;
   op->data.send_status_from_server.trailing_metadata_count = 0;
@@ -159,14 +159,14 @@ static void simple_request_body(grpc_end2end_test_config config,
   grpc_slice status_details = grpc_slice_from_static_string("xyz");
   op->data.send_status_from_server.status_details = &status_details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_CLOSE_ON_SERVER;
   op->data.recv_close_on_server.cancelled = &was_cancelled;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(102), NULL);
+  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(102), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   CQ_EXPECT_COMPLETION(cqv, tag(102), 1);
@@ -228,7 +228,7 @@ static void test_max_concurrent_streams(grpc_end2end_test_config config) {
   server_args.num_args = 1;
   server_args.args = &server_arg;
 
-  f = begin_test(config, "test_max_concurrent_streams", NULL, &server_args);
+  f = begin_test(config, "test_max_concurrent_streams", nullptr, &server_args);
   cqv = cq_verifier_create(f.cq);
 
   grpc_metadata_array_init(&request_metadata_recv);
@@ -248,16 +248,16 @@ static void test_max_concurrent_streams(grpc_end2end_test_config config) {
      the first completes */
   deadline = n_seconds_from_now(1000);
   c1 = grpc_channel_create_call(
-      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+      f.client, nullptr, GRPC_PROPAGATE_DEFAULTS, f.cq,
       grpc_slice_from_static_string("/alpha"),
       get_host_override_slice("foo.test.google.fr:1234", config), deadline,
-      NULL);
+      nullptr);
   GPR_ASSERT(c1);
   c2 = grpc_channel_create_call(
-      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+      f.client, nullptr, GRPC_PROPAGATE_DEFAULTS, f.cq,
       grpc_slice_from_static_string("/beta"),
       get_host_override_slice("foo.test.google.fr:1234", config), deadline,
-      NULL);
+      nullptr);
   GPR_ASSERT(c2);
 
   GPR_ASSERT(GRPC_CALL_OK == grpc_server_request_call(
@@ -269,13 +269,13 @@ static void test_max_concurrent_streams(grpc_end2end_test_config config) {
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
   op->data.send_initial_metadata.count = 0;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_CLOSE_FROM_CLIENT;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(c1, ops, (size_t)(op - ops), tag(301), NULL);
+  error = grpc_call_start_batch(c1, ops, (size_t)(op - ops), tag(301), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   memset(ops, 0, sizeof(ops));
@@ -285,15 +285,15 @@ static void test_max_concurrent_streams(grpc_end2end_test_config config) {
   op->data.recv_status_on_client.status = &status1;
   op->data.recv_status_on_client.status_details = &details1;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_INITIAL_METADATA;
   op->data.recv_initial_metadata.recv_initial_metadata =
       &initial_metadata_recv1;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(c1, ops, (size_t)(op - ops), tag(302), NULL);
+  error = grpc_call_start_batch(c1, ops, (size_t)(op - ops), tag(302), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   memset(ops, 0, sizeof(ops));
@@ -301,13 +301,13 @@ static void test_max_concurrent_streams(grpc_end2end_test_config config) {
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
   op->data.send_initial_metadata.count = 0;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_CLOSE_FROM_CLIENT;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(c2, ops, (size_t)(op - ops), tag(401), NULL);
+  error = grpc_call_start_batch(c2, ops, (size_t)(op - ops), tag(401), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   memset(ops, 0, sizeof(ops));
@@ -317,15 +317,15 @@ static void test_max_concurrent_streams(grpc_end2end_test_config config) {
   op->data.recv_status_on_client.status = &status2;
   op->data.recv_status_on_client.status_details = &details2;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_INITIAL_METADATA;
   op->data.recv_initial_metadata.recv_initial_metadata =
       &initial_metadata_recv1;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(c2, ops, (size_t)(op - ops), tag(402), NULL);
+  error = grpc_call_start_batch(c2, ops, (size_t)(op - ops), tag(402), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   got_client_start = 0;
@@ -333,7 +333,7 @@ static void test_max_concurrent_streams(grpc_end2end_test_config config) {
   live_call = -1;
   while (!got_client_start || !got_server_start) {
     ev = grpc_completion_queue_next(f.cq, grpc_timeout_seconds_to_deadline(3),
-                                    NULL);
+                                    nullptr);
     GPR_ASSERT(ev.type == GRPC_OP_COMPLETE);
     GPR_ASSERT(ev.success);
     if (ev.tag == tag(101)) {
@@ -357,12 +357,12 @@ static void test_max_concurrent_streams(grpc_end2end_test_config config) {
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
   op->data.send_initial_metadata.count = 0;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_CLOSE_ON_SERVER;
   op->data.recv_close_on_server.cancelled = &was_cancelled;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_STATUS_FROM_SERVER;
   op->data.send_status_from_server.trailing_metadata_count = 0;
@@ -370,9 +370,9 @@ static void test_max_concurrent_streams(grpc_end2end_test_config config) {
   grpc_slice status_details = grpc_slice_from_static_string("xyz");
   op->data.send_status_from_server.status_details = &status_details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(s1, ops, (size_t)(op - ops), tag(102), NULL);
+  error = grpc_call_start_batch(s1, ops, (size_t)(op - ops), tag(102), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   CQ_EXPECT_COMPLETION(cqv, tag(102), 1);
@@ -395,21 +395,21 @@ static void test_max_concurrent_streams(grpc_end2end_test_config config) {
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
   op->data.send_initial_metadata.count = 0;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_CLOSE_ON_SERVER;
   op->data.recv_close_on_server.cancelled = &was_cancelled;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_STATUS_FROM_SERVER;
   op->data.send_status_from_server.trailing_metadata_count = 0;
   op->data.send_status_from_server.status = GRPC_STATUS_UNIMPLEMENTED;
   op->data.send_status_from_server.status_details = &status_details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(s2, ops, (size_t)(op - ops), tag(202), NULL);
+  error = grpc_call_start_batch(s2, ops, (size_t)(op - ops), tag(202), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   CQ_EXPECT_COMPLETION(cqv, tag(live_call + 2), 1);
@@ -469,7 +469,7 @@ static void test_max_concurrent_streams_with_timeout_on_first(
   server_args.args = &server_arg;
 
   f = begin_test(config, "test_max_concurrent_streams_with_timeout_on_first",
-                 NULL, &server_args);
+                 nullptr, &server_args);
   cqv = cq_verifier_create(f.cq);
 
   grpc_metadata_array_init(&request_metadata_recv);
@@ -488,16 +488,16 @@ static void test_max_concurrent_streams_with_timeout_on_first(
   /* start two requests - ensuring that the second is not accepted until
      the first completes */
   c1 = grpc_channel_create_call(
-      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+      f.client, nullptr, GRPC_PROPAGATE_DEFAULTS, f.cq,
       grpc_slice_from_static_string("/alpha"),
       get_host_override_slice("foo.test.google.fr:1234", config),
-      n_seconds_from_now(3), NULL);
+      n_seconds_from_now(3), nullptr);
   GPR_ASSERT(c1);
   c2 = grpc_channel_create_call(
-      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+      f.client, nullptr, GRPC_PROPAGATE_DEFAULTS, f.cq,
       grpc_slice_from_static_string("/beta"),
       get_host_override_slice("foo.test.google.fr:1234", config),
-      n_seconds_from_now(1000), NULL);
+      n_seconds_from_now(1000), nullptr);
   GPR_ASSERT(c2);
 
   GPR_ASSERT(GRPC_CALL_OK == grpc_server_request_call(
@@ -509,13 +509,13 @@ static void test_max_concurrent_streams_with_timeout_on_first(
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
   op->data.send_initial_metadata.count = 0;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_CLOSE_FROM_CLIENT;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(c1, ops, (size_t)(op - ops), tag(301), NULL);
+  error = grpc_call_start_batch(c1, ops, (size_t)(op - ops), tag(301), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   memset(ops, 0, sizeof(ops));
@@ -525,15 +525,15 @@ static void test_max_concurrent_streams_with_timeout_on_first(
   op->data.recv_status_on_client.status = &status1;
   op->data.recv_status_on_client.status_details = &details1;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_INITIAL_METADATA;
   op->data.recv_initial_metadata.recv_initial_metadata =
       &initial_metadata_recv1;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(c1, ops, (size_t)(op - ops), tag(302), NULL);
+  error = grpc_call_start_batch(c1, ops, (size_t)(op - ops), tag(302), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   CQ_EXPECT_COMPLETION(cqv, tag(101), 1);
@@ -545,13 +545,13 @@ static void test_max_concurrent_streams_with_timeout_on_first(
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
   op->data.send_initial_metadata.count = 0;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_CLOSE_FROM_CLIENT;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(c2, ops, (size_t)(op - ops), tag(401), NULL);
+  error = grpc_call_start_batch(c2, ops, (size_t)(op - ops), tag(401), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   memset(ops, 0, sizeof(ops));
@@ -561,15 +561,15 @@ static void test_max_concurrent_streams_with_timeout_on_first(
   op->data.recv_status_on_client.status = &status2;
   op->data.recv_status_on_client.status_details = &details2;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_INITIAL_METADATA;
   op->data.recv_initial_metadata.recv_initial_metadata =
       &initial_metadata_recv2;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(c2, ops, (size_t)(op - ops), tag(402), NULL);
+  error = grpc_call_start_batch(c2, ops, (size_t)(op - ops), tag(402), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   grpc_call_details_destroy(&call_details);
@@ -589,12 +589,12 @@ static void test_max_concurrent_streams_with_timeout_on_first(
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
   op->data.send_initial_metadata.count = 0;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_CLOSE_ON_SERVER;
   op->data.recv_close_on_server.cancelled = &was_cancelled;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_STATUS_FROM_SERVER;
   op->data.send_status_from_server.trailing_metadata_count = 0;
@@ -602,9 +602,9 @@ static void test_max_concurrent_streams_with_timeout_on_first(
   grpc_slice status_details = grpc_slice_from_static_string("xyz");
   op->data.send_status_from_server.status_details = &status_details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(s2, ops, (size_t)(op - ops), tag(202), NULL);
+  error = grpc_call_start_batch(s2, ops, (size_t)(op - ops), tag(202), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   CQ_EXPECT_COMPLETION(cqv, tag(402), 1);
@@ -663,7 +663,7 @@ static void test_max_concurrent_streams_with_timeout_on_second(
   server_args.args = &server_arg;
 
   f = begin_test(config, "test_max_concurrent_streams_with_timeout_on_second",
-                 NULL, &server_args);
+                 nullptr, &server_args);
   cqv = cq_verifier_create(f.cq);
 
   grpc_metadata_array_init(&request_metadata_recv);
@@ -683,16 +683,16 @@ static void test_max_concurrent_streams_with_timeout_on_second(
      the first completes , and the second request will timeout in the
      concurrent_list */
   c1 = grpc_channel_create_call(
-      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+      f.client, nullptr, GRPC_PROPAGATE_DEFAULTS, f.cq,
       grpc_slice_from_static_string("/alpha"),
       get_host_override_slice("foo.test.google.fr:1234", config),
-      n_seconds_from_now(1000), NULL);
+      n_seconds_from_now(1000), nullptr);
   GPR_ASSERT(c1);
   c2 = grpc_channel_create_call(
-      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+      f.client, nullptr, GRPC_PROPAGATE_DEFAULTS, f.cq,
       grpc_slice_from_static_string("/beta"),
       get_host_override_slice("foo.test.google.fr:1234", config),
-      n_seconds_from_now(3), NULL);
+      n_seconds_from_now(3), nullptr);
   GPR_ASSERT(c2);
 
   GPR_ASSERT(GRPC_CALL_OK == grpc_server_request_call(
@@ -704,13 +704,13 @@ static void test_max_concurrent_streams_with_timeout_on_second(
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
   op->data.send_initial_metadata.count = 0;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_CLOSE_FROM_CLIENT;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(c1, ops, (size_t)(op - ops), tag(301), NULL);
+  error = grpc_call_start_batch(c1, ops, (size_t)(op - ops), tag(301), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   memset(ops, 0, sizeof(ops));
@@ -720,15 +720,15 @@ static void test_max_concurrent_streams_with_timeout_on_second(
   op->data.recv_status_on_client.status = &status1;
   op->data.recv_status_on_client.status_details = &details1;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_INITIAL_METADATA;
   op->data.recv_initial_metadata.recv_initial_metadata =
       &initial_metadata_recv1;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(c1, ops, (size_t)(op - ops), tag(302), NULL);
+  error = grpc_call_start_batch(c1, ops, (size_t)(op - ops), tag(302), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   CQ_EXPECT_COMPLETION(cqv, tag(101), 1);
@@ -740,13 +740,13 @@ static void test_max_concurrent_streams_with_timeout_on_second(
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
   op->data.send_initial_metadata.count = 0;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_CLOSE_FROM_CLIENT;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(c2, ops, (size_t)(op - ops), tag(401), NULL);
+  error = grpc_call_start_batch(c2, ops, (size_t)(op - ops), tag(401), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   memset(ops, 0, sizeof(ops));
@@ -756,15 +756,15 @@ static void test_max_concurrent_streams_with_timeout_on_second(
   op->data.recv_status_on_client.status = &status2;
   op->data.recv_status_on_client.status_details = &details2;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_INITIAL_METADATA;
   op->data.recv_initial_metadata.recv_initial_metadata =
       &initial_metadata_recv2;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(c2, ops, (size_t)(op - ops), tag(402), NULL);
+  error = grpc_call_start_batch(c2, ops, (size_t)(op - ops), tag(402), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   /* the second request is time out*/
@@ -782,12 +782,12 @@ static void test_max_concurrent_streams_with_timeout_on_second(
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
   op->data.send_initial_metadata.count = 0;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_CLOSE_ON_SERVER;
   op->data.recv_close_on_server.cancelled = &was_cancelled;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_STATUS_FROM_SERVER;
   op->data.send_status_from_server.trailing_metadata_count = 0;
@@ -795,9 +795,9 @@ static void test_max_concurrent_streams_with_timeout_on_second(
   grpc_slice status_details = grpc_slice_from_static_string("xyz");
   op->data.send_status_from_server.status_details = &status_details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(s1, ops, (size_t)(op - ops), tag(102), NULL);
+  error = grpc_call_start_batch(s1, ops, (size_t)(op - ops), tag(102), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   CQ_EXPECT_COMPLETION(cqv, tag(302), 1);
diff --git a/test/core/end2end/tests/max_connection_age.cc b/test/core/end2end/tests/max_connection_age.cc
index b5d4dcf963..ddccfc3b51 100644
--- a/test/core/end2end/tests/max_connection_age.cc
+++ b/test/core/end2end/tests/max_connection_age.cc
@@ -51,20 +51,20 @@ static void drain_cq(grpc_completion_queue* cq) {
   grpc_event ev;
   do {
     ev = grpc_completion_queue_next(cq, grpc_timeout_seconds_to_deadline(5),
-                                    NULL);
+                                    nullptr);
   } while (ev.type != GRPC_QUEUE_SHUTDOWN);
 }
 
 static void shutdown_server(grpc_end2end_test_fixture* f) {
   if (!f->server) return;
   grpc_server_destroy(f->server);
-  f->server = NULL;
+  f->server = nullptr;
 }
 
 static void shutdown_client(grpc_end2end_test_fixture* f) {
   if (!f->client) return;
   grpc_channel_destroy(f->client);
-  f->client = NULL;
+  f->client = nullptr;
 }
 
 static void end_test(grpc_end2end_test_fixture* f) {
@@ -78,7 +78,7 @@ static void end_test(grpc_end2end_test_fixture* f) {
 }
 
 static void test_max_age_forcibly_close(grpc_end2end_test_config config) {
-  grpc_end2end_test_fixture f = config.create_fixture(NULL, NULL);
+  grpc_end2end_test_fixture f = config.create_fixture(nullptr, nullptr);
   cq_verifier* cqv = cq_verifier_create(f.cq);
   grpc_arg server_a[3];
   server_a[0].type = GRPC_ARG_INTEGER;
@@ -92,7 +92,7 @@ static void test_max_age_forcibly_close(grpc_end2end_test_config config) {
   server_a[2].value.integer = MAX_CONNECTION_IDLE_MS;
   grpc_channel_args server_args = {GPR_ARRAY_SIZE(server_a), server_a};
 
-  config.init_client(&f, NULL);
+  config.init_client(&f, nullptr);
   config.init_server(&f, &server_args);
 
   grpc_call* c;
@@ -110,10 +110,10 @@ static void test_max_age_forcibly_close(grpc_end2end_test_config config) {
   int was_cancelled = 2;
 
   c = grpc_channel_create_call(
-      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+      f.client, nullptr, GRPC_PROPAGATE_DEFAULTS, f.cq,
       grpc_slice_from_static_string("/foo"),
       get_host_override_slice("foo.test.google.fr:1234", config), deadline,
-      NULL);
+      nullptr);
   GPR_ASSERT(c);
 
   grpc_metadata_array_init(&initial_metadata_recv);
@@ -125,27 +125,27 @@ static void test_max_age_forcibly_close(grpc_end2end_test_config config) {
   op = ops;
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
   op->data.send_initial_metadata.count = 0;
-  op->data.send_initial_metadata.metadata = NULL;
+  op->data.send_initial_metadata.metadata = nullptr;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_CLOSE_FROM_CLIENT;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_INITIAL_METADATA;
   op->data.recv_initial_metadata.recv_initial_metadata = &initial_metadata_recv;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_STATUS_ON_CLIENT;
   op->data.recv_status_on_client.trailing_metadata = &trailing_metadata_recv;
   op->data.recv_status_on_client.status = &status;
   op->data.recv_status_on_client.status_details = &details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), NULL);
+  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   error =
@@ -175,7 +175,7 @@ static void test_max_age_forcibly_close(grpc_end2end_test_config config) {
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
   op->data.send_initial_metadata.count = 0;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_STATUS_FROM_SERVER;
   op->data.send_status_from_server.trailing_metadata_count = 0;
@@ -183,14 +183,14 @@ static void test_max_age_forcibly_close(grpc_end2end_test_config config) {
   grpc_slice status_details = grpc_slice_from_static_string("xyz");
   op->data.send_status_from_server.status_details = &status_details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_CLOSE_ON_SERVER;
   op->data.recv_close_on_server.cancelled = &was_cancelled;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(102), NULL);
+  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(102), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
   CQ_EXPECT_COMPLETION(cqv, tag(102), true);
   cq_verify(cqv);
@@ -221,7 +221,7 @@ static void test_max_age_forcibly_close(grpc_end2end_test_config config) {
 }
 
 static void test_max_age_gracefully_close(grpc_end2end_test_config config) {
-  grpc_end2end_test_fixture f = config.create_fixture(NULL, NULL);
+  grpc_end2end_test_fixture f = config.create_fixture(nullptr, nullptr);
   cq_verifier* cqv = cq_verifier_create(f.cq);
   grpc_arg server_a[3];
   server_a[0].type = GRPC_ARG_INTEGER;
@@ -235,7 +235,7 @@ static void test_max_age_gracefully_close(grpc_end2end_test_config config) {
   server_a[2].value.integer = MAX_CONNECTION_IDLE_MS;
   grpc_channel_args server_args = {GPR_ARRAY_SIZE(server_a), server_a};
 
-  config.init_client(&f, NULL);
+  config.init_client(&f, nullptr);
   config.init_server(&f, &server_args);
 
   grpc_call* c;
@@ -253,10 +253,10 @@ static void test_max_age_gracefully_close(grpc_end2end_test_config config) {
   int was_cancelled = 2;
 
   c = grpc_channel_create_call(
-      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+      f.client, nullptr, GRPC_PROPAGATE_DEFAULTS, f.cq,
       grpc_slice_from_static_string("/foo"),
       get_host_override_slice("foo.test.google.fr:1234", config), deadline,
-      NULL);
+      nullptr);
   GPR_ASSERT(c);
 
   grpc_metadata_array_init(&initial_metadata_recv);
@@ -268,27 +268,27 @@ static void test_max_age_gracefully_close(grpc_end2end_test_config config) {
   op = ops;
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
   op->data.send_initial_metadata.count = 0;
-  op->data.send_initial_metadata.metadata = NULL;
+  op->data.send_initial_metadata.metadata = nullptr;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_CLOSE_FROM_CLIENT;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_INITIAL_METADATA;
   op->data.recv_initial_metadata.recv_initial_metadata = &initial_metadata_recv;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_STATUS_ON_CLIENT;
   op->data.recv_status_on_client.trailing_metadata = &trailing_metadata_recv;
   op->data.recv_status_on_client.status = &status;
   op->data.recv_status_on_client.status_details = &details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), NULL);
+  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   error =
@@ -310,7 +310,7 @@ static void test_max_age_gracefully_close(grpc_end2end_test_config config) {
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
   op->data.send_initial_metadata.count = 0;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_STATUS_FROM_SERVER;
   op->data.send_status_from_server.trailing_metadata_count = 0;
@@ -318,14 +318,14 @@ static void test_max_age_gracefully_close(grpc_end2end_test_config config) {
   grpc_slice status_details = grpc_slice_from_static_string("xyz");
   op->data.send_status_from_server.status_details = &status_details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_CLOSE_ON_SERVER;
   op->data.recv_close_on_server.cancelled = &was_cancelled;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(102), NULL);
+  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(102), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   CQ_EXPECT_COMPLETION(cqv, tag(102), true);
diff --git a/test/core/end2end/tests/max_connection_idle.cc b/test/core/end2end/tests/max_connection_idle.cc
index d850e4267b..293ff7d1f2 100644
--- a/test/core/end2end/tests/max_connection_idle.cc
+++ b/test/core/end2end/tests/max_connection_idle.cc
@@ -38,7 +38,7 @@ static void drain_cq(grpc_completion_queue* cq) {
   grpc_event ev;
   do {
     ev = grpc_completion_queue_next(cq, grpc_timeout_seconds_to_deadline(5),
-                                    NULL);
+                                    nullptr);
   } while (ev.type != GRPC_QUEUE_SHUTDOWN);
 }
 
@@ -61,14 +61,14 @@ static void simple_request_body(grpc_end2end_test_config config,
 
   gpr_timespec deadline = grpc_timeout_seconds_to_deadline(5);
   c = grpc_channel_create_call(
-      f->client, NULL, GRPC_PROPAGATE_DEFAULTS, f->cq,
+      f->client, nullptr, GRPC_PROPAGATE_DEFAULTS, f->cq,
       grpc_slice_from_static_string("/foo"),
       get_host_override_slice("foo.test.google.fr:1234", config), deadline,
-      NULL);
+      nullptr);
   GPR_ASSERT(c);
 
   peer = grpc_call_get_peer(c);
-  GPR_ASSERT(peer != NULL);
+  GPR_ASSERT(peer != nullptr);
   gpr_log(GPR_DEBUG, "client_peer_before_call=%s", peer);
   gpr_free(peer);
 
@@ -82,25 +82,25 @@ static void simple_request_body(grpc_end2end_test_config config,
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
   op->data.send_initial_metadata.count = 0;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_CLOSE_FROM_CLIENT;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_INITIAL_METADATA;
   op->data.recv_initial_metadata.recv_initial_metadata = &initial_metadata_recv;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_STATUS_ON_CLIENT;
   op->data.recv_status_on_client.trailing_metadata = &trailing_metadata_recv;
   op->data.recv_status_on_client.status = &status;
   op->data.recv_status_on_client.status_details = &details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), NULL);
+  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   error =
@@ -111,11 +111,11 @@ static void simple_request_body(grpc_end2end_test_config config,
   cq_verify(cqv);
 
   peer = grpc_call_get_peer(s);
-  GPR_ASSERT(peer != NULL);
+  GPR_ASSERT(peer != nullptr);
   gpr_log(GPR_DEBUG, "server_peer=%s", peer);
   gpr_free(peer);
   peer = grpc_call_get_peer(c);
-  GPR_ASSERT(peer != NULL);
+  GPR_ASSERT(peer != nullptr);
   gpr_log(GPR_DEBUG, "client_peer=%s", peer);
   gpr_free(peer);
 
@@ -124,7 +124,7 @@ static void simple_request_body(grpc_end2end_test_config config,
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
   op->data.send_initial_metadata.count = 0;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_STATUS_FROM_SERVER;
   op->data.send_status_from_server.trailing_metadata_count = 0;
@@ -132,14 +132,14 @@ static void simple_request_body(grpc_end2end_test_config config,
   grpc_slice status_details = grpc_slice_from_static_string("xyz");
   op->data.send_status_from_server.status_details = &status_details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_CLOSE_ON_SERVER;
   op->data.recv_close_on_server.cancelled = &was_cancelled;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(102), NULL);
+  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(102), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   CQ_EXPECT_COMPLETION(cqv, tag(102), 1);
@@ -167,7 +167,7 @@ static void simple_request_body(grpc_end2end_test_config config,
 }
 
 static void test_max_connection_idle(grpc_end2end_test_config config) {
-  grpc_end2end_test_fixture f = config.create_fixture(NULL, NULL);
+  grpc_end2end_test_fixture f = config.create_fixture(nullptr, nullptr);
   grpc_connectivity_state state = GRPC_CHANNEL_IDLE;
   cq_verifier* cqv = cq_verifier_create(f.cq);
 
diff --git a/test/core/end2end/tests/max_message_length.cc b/test/core/end2end/tests/max_message_length.cc
index 3d677f1d8f..e9c3785057 100644
--- a/test/core/end2end/tests/max_message_length.cc
+++ b/test/core/end2end/tests/max_message_length.cc
@@ -45,7 +45,7 @@ static grpc_end2end_test_fixture begin_test(grpc_end2end_test_config config,
   // We intentionally do not pass the client and server args to
   // create_fixture(), since we don't want the limit enforced on the
   // proxy, only on the backend server.
-  f = config.create_fixture(NULL, NULL);
+  f = config.create_fixture(nullptr, nullptr);
   config.init_server(&f, server_args);
   config.init_client(&f, client_args);
   return f;
@@ -62,7 +62,7 @@ static gpr_timespec five_seconds_from_now(void) {
 static void drain_cq(grpc_completion_queue* cq) {
   grpc_event ev;
   do {
-    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), NULL);
+    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), nullptr);
   } while (ev.type != GRPC_QUEUE_SHUTDOWN);
 }
 
@@ -70,17 +70,17 @@ static void shutdown_server(grpc_end2end_test_fixture* f) {
   if (!f->server) return;
   grpc_server_shutdown_and_notify(f->server, f->cq, tag(1000));
   grpc_event ev = grpc_completion_queue_next(
-      f->cq, grpc_timeout_seconds_to_deadline(5), NULL);
+      f->cq, grpc_timeout_seconds_to_deadline(5), nullptr);
   GPR_ASSERT(ev.type == GRPC_OP_COMPLETE);
   GPR_ASSERT(ev.tag == tag(1000));
   grpc_server_destroy(f->server);
-  f->server = NULL;
+  f->server = nullptr;
 }
 
 static void shutdown_client(grpc_end2end_test_fixture* f) {
   if (!f->client) return;
   grpc_channel_destroy(f->client);
-  f->client = NULL;
+  f->client = nullptr;
 }
 
 static void end_test(grpc_end2end_test_fixture* f) {
@@ -106,8 +106,8 @@ static void test_max_message_length_on_request(grpc_end2end_test_config config,
           send_limit, use_service_config, use_string_json_value);
 
   grpc_end2end_test_fixture f;
-  grpc_call* c = NULL;
-  grpc_call* s = NULL;
+  grpc_call* c = nullptr;
+  grpc_call* s = nullptr;
   cq_verifier* cqv;
   grpc_op ops[6];
   grpc_op* op;
@@ -115,7 +115,7 @@ static void test_max_message_length_on_request(grpc_end2end_test_config config,
       grpc_slice_from_copied_string("hello world");
   grpc_byte_buffer* request_payload =
       grpc_raw_byte_buffer_create(&request_payload_slice, 1);
-  grpc_byte_buffer* recv_payload = NULL;
+  grpc_byte_buffer* recv_payload = nullptr;
   grpc_metadata_array initial_metadata_recv;
   grpc_metadata_array trailing_metadata_recv;
   grpc_metadata_array request_metadata_recv;
@@ -125,8 +125,8 @@ static void test_max_message_length_on_request(grpc_end2end_test_config config,
   grpc_slice details;
   int was_cancelled = 2;
 
-  grpc_channel_args* client_args = NULL;
-  grpc_channel_args* server_args = NULL;
+  grpc_channel_args* client_args = nullptr;
+  grpc_channel_args* server_args = nullptr;
   if (use_service_config) {
     // We don't currently support service configs on the server side.
     GPR_ASSERT(send_limit);
@@ -153,7 +153,7 @@ static void test_max_message_length_on_request(grpc_end2end_test_config config,
                   "    \"maxRequestMessageBytes\": 5\n"
                   "  } ]\n"
                   "}");
-    client_args = grpc_channel_args_copy_and_add(NULL, &arg, 1);
+    client_args = grpc_channel_args_copy_and_add(nullptr, &arg, 1);
   } else {
     // Set limit via channel args.
     grpc_arg arg;
@@ -162,7 +162,7 @@ static void test_max_message_length_on_request(grpc_end2end_test_config config,
                   : const_cast<char*>(GRPC_ARG_MAX_RECEIVE_MESSAGE_LENGTH);
     arg.type = GRPC_ARG_INTEGER;
     arg.value.integer = 5;
-    grpc_channel_args* args = grpc_channel_args_copy_and_add(NULL, &arg, 1);
+    grpc_channel_args* args = grpc_channel_args_copy_and_add(nullptr, &arg, 1);
     if (send_limit) {
       client_args = args;
     } else {
@@ -174,18 +174,18 @@ static void test_max_message_length_on_request(grpc_end2end_test_config config,
                  server_args);
   {
     grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
-    if (client_args != NULL) grpc_channel_args_destroy(&exec_ctx, client_args);
-    if (server_args != NULL) grpc_channel_args_destroy(&exec_ctx, server_args);
+    if (client_args != nullptr) grpc_channel_args_destroy(&exec_ctx, client_args);
+    if (server_args != nullptr) grpc_channel_args_destroy(&exec_ctx, server_args);
     grpc_exec_ctx_finish(&exec_ctx);
   }
 
   cqv = cq_verifier_create(f.cq);
 
   c = grpc_channel_create_call(
-      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+      f.client, nullptr, GRPC_PROPAGATE_DEFAULTS, f.cq,
       grpc_slice_from_static_string("/service/method"),
       get_host_override_slice("foo.test.google.fr:1234", config),
-      gpr_inf_future(GPR_CLOCK_REALTIME), NULL);
+      gpr_inf_future(GPR_CLOCK_REALTIME), nullptr);
   GPR_ASSERT(c);
 
   grpc_metadata_array_init(&initial_metadata_recv);
@@ -198,30 +198,30 @@ static void test_max_message_length_on_request(grpc_end2end_test_config config,
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
   op->data.send_initial_metadata.count = 0;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_MESSAGE;
   op->data.send_message.send_message = request_payload;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_CLOSE_FROM_CLIENT;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_INITIAL_METADATA;
   op->data.recv_initial_metadata.recv_initial_metadata = &initial_metadata_recv;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_STATUS_ON_CLIENT;
   op->data.recv_status_on_client.trailing_metadata = &trailing_metadata_recv;
   op->data.recv_status_on_client.status = &status;
   op->data.recv_status_on_client.status_details = &details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), NULL);
+  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   if (send_limit) {
@@ -242,14 +242,14 @@ static void test_max_message_length_on_request(grpc_end2end_test_config config,
   op->op = GRPC_OP_RECV_CLOSE_ON_SERVER;
   op->data.recv_close_on_server.cancelled = &was_cancelled;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_MESSAGE;
   op->data.recv_message.recv_message = &recv_payload;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(102), NULL);
+  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(102), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   CQ_EXPECT_COMPLETION(cqv, tag(102), 1);
@@ -278,7 +278,7 @@ done:
   grpc_byte_buffer_destroy(recv_payload);
 
   grpc_call_unref(c);
-  if (s != NULL) grpc_call_unref(s);
+  if (s != nullptr) grpc_call_unref(s);
 
   cq_verifier_destroy(cqv);
 
@@ -299,8 +299,8 @@ static void test_max_message_length_on_response(grpc_end2end_test_config config,
           send_limit, use_service_config, use_string_json_value);
 
   grpc_end2end_test_fixture f;
-  grpc_call* c = NULL;
-  grpc_call* s = NULL;
+  grpc_call* c = nullptr;
+  grpc_call* s = nullptr;
   cq_verifier* cqv;
   grpc_op ops[6];
   grpc_op* op;
@@ -308,7 +308,7 @@ static void test_max_message_length_on_response(grpc_end2end_test_config config,
       grpc_slice_from_copied_string("hello world");
   grpc_byte_buffer* response_payload =
       grpc_raw_byte_buffer_create(&response_payload_slice, 1);
-  grpc_byte_buffer* recv_payload = NULL;
+  grpc_byte_buffer* recv_payload = nullptr;
   grpc_metadata_array initial_metadata_recv;
   grpc_metadata_array trailing_metadata_recv;
   grpc_metadata_array request_metadata_recv;
@@ -318,8 +318,8 @@ static void test_max_message_length_on_response(grpc_end2end_test_config config,
   grpc_slice details;
   int was_cancelled = 2;
 
-  grpc_channel_args* client_args = NULL;
-  grpc_channel_args* server_args = NULL;
+  grpc_channel_args* client_args = nullptr;
+  grpc_channel_args* server_args = nullptr;
   if (use_service_config) {
     // We don't currently support service configs on the server side.
     GPR_ASSERT(!send_limit);
@@ -344,7 +344,7 @@ static void test_max_message_length_on_response(grpc_end2end_test_config config,
               "    \"maxResponseMessageBytes\": 5\n"
               "  } ]\n"
               "}");
-    client_args = grpc_channel_args_copy_and_add(NULL, &arg, 1);
+    client_args = grpc_channel_args_copy_and_add(nullptr, &arg, 1);
   } else {
     // Set limit via channel args.
     grpc_arg arg;
@@ -353,7 +353,7 @@ static void test_max_message_length_on_response(grpc_end2end_test_config config,
                   : const_cast<char*>(GRPC_ARG_MAX_RECEIVE_MESSAGE_LENGTH);
     arg.type = GRPC_ARG_INTEGER;
     arg.value.integer = 5;
-    grpc_channel_args* args = grpc_channel_args_copy_and_add(NULL, &arg, 1);
+    grpc_channel_args* args = grpc_channel_args_copy_and_add(nullptr, &arg, 1);
     if (send_limit) {
       server_args = args;
     } else {
@@ -365,17 +365,17 @@ static void test_max_message_length_on_response(grpc_end2end_test_config config,
                  server_args);
   {
     grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
-    if (client_args != NULL) grpc_channel_args_destroy(&exec_ctx, client_args);
-    if (server_args != NULL) grpc_channel_args_destroy(&exec_ctx, server_args);
+    if (client_args != nullptr) grpc_channel_args_destroy(&exec_ctx, client_args);
+    if (server_args != nullptr) grpc_channel_args_destroy(&exec_ctx, server_args);
     grpc_exec_ctx_finish(&exec_ctx);
   }
   cqv = cq_verifier_create(f.cq);
 
   c = grpc_channel_create_call(
-      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+      f.client, nullptr, GRPC_PROPAGATE_DEFAULTS, f.cq,
       grpc_slice_from_static_string("/service/method"),
       get_host_override_slice("foo.test.google.fr:1234", config),
-      gpr_inf_future(GPR_CLOCK_REALTIME), NULL);
+      gpr_inf_future(GPR_CLOCK_REALTIME), nullptr);
   GPR_ASSERT(c);
 
   grpc_metadata_array_init(&initial_metadata_recv);
@@ -388,30 +388,30 @@ static void test_max_message_length_on_response(grpc_end2end_test_config config,
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
   op->data.send_initial_metadata.count = 0;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_CLOSE_FROM_CLIENT;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_INITIAL_METADATA;
   op->data.recv_initial_metadata.recv_initial_metadata = &initial_metadata_recv;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_MESSAGE;
   op->data.recv_message.recv_message = &recv_payload;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_STATUS_ON_CLIENT;
   op->data.recv_status_on_client.trailing_metadata = &trailing_metadata_recv;
   op->data.recv_status_on_client.status = &status;
   op->data.recv_status_on_client.status_details = &details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), NULL);
+  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   error =
@@ -426,17 +426,17 @@ static void test_max_message_length_on_response(grpc_end2end_test_config config,
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
   op->data.send_initial_metadata.count = 0;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_CLOSE_ON_SERVER;
   op->data.recv_close_on_server.cancelled = &was_cancelled;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_MESSAGE;
   op->data.send_message.send_message = response_payload;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_STATUS_FROM_SERVER;
   op->data.send_status_from_server.trailing_metadata_count = 0;
@@ -444,9 +444,9 @@ static void test_max_message_length_on_response(grpc_end2end_test_config config,
   grpc_slice status_details = grpc_slice_from_static_string("xyz");
   op->data.send_status_from_server.status_details = &status_details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(102), NULL);
+  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(102), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   CQ_EXPECT_COMPLETION(cqv, tag(102), 1);
@@ -473,7 +473,7 @@ static void test_max_message_length_on_response(grpc_end2end_test_config config,
   grpc_byte_buffer_destroy(recv_payload);
 
   grpc_call_unref(c);
-  if (s != NULL) grpc_call_unref(s);
+  if (s != nullptr) grpc_call_unref(s);
 
   cq_verifier_destroy(cqv);
 
diff --git a/test/core/end2end/tests/negative_deadline.cc b/test/core/end2end/tests/negative_deadline.cc
index 0d56038684..b793964b48 100644
--- a/test/core/end2end/tests/negative_deadline.cc
+++ b/test/core/end2end/tests/negative_deadline.cc
@@ -55,7 +55,7 @@ static gpr_timespec five_seconds_from_now(void) {
 static void drain_cq(grpc_completion_queue* cq) {
   grpc_event ev;
   do {
-    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), NULL);
+    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), nullptr);
   } while (ev.type != GRPC_QUEUE_SHUTDOWN);
 }
 
@@ -64,16 +64,16 @@ static void shutdown_server(grpc_end2end_test_fixture* f) {
   grpc_server_shutdown_and_notify(f->server, f->shutdown_cq, tag(1000));
   GPR_ASSERT(grpc_completion_queue_pluck(f->shutdown_cq, tag(1000),
                                          grpc_timeout_seconds_to_deadline(5),
-                                         NULL)
+                                         nullptr)
                  .type == GRPC_OP_COMPLETE);
   grpc_server_destroy(f->server);
-  f->server = NULL;
+  f->server = nullptr;
 }
 
 static void shutdown_client(grpc_end2end_test_fixture* f) {
   if (!f->client) return;
   grpc_channel_destroy(f->client);
-  f->client = NULL;
+  f->client = nullptr;
 }
 
 static void end_test(grpc_end2end_test_fixture* f) {
@@ -102,10 +102,10 @@ static void simple_request_body(grpc_end2end_test_config config,
 
   gpr_timespec deadline = gpr_inf_past(GPR_CLOCK_REALTIME);
   c = grpc_channel_create_call(
-      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+      f.client, nullptr, GRPC_PROPAGATE_DEFAULTS, f.cq,
       grpc_slice_from_static_string("/foo"),
       get_host_override_slice("foo.test.google.fr:1234", config), deadline,
-      NULL);
+      nullptr);
   GPR_ASSERT(c);
 
   grpc_metadata_array_init(&initial_metadata_recv);
@@ -118,24 +118,24 @@ static void simple_request_body(grpc_end2end_test_config config,
   op->data.recv_status_on_client.status = &status;
   op->data.recv_status_on_client.status_details = &details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_INITIAL_METADATA;
   op->data.recv_initial_metadata.recv_initial_metadata = &initial_metadata_recv;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
   op->data.send_initial_metadata.count = 0;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_CLOSE_FROM_CLIENT;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   GPR_ASSERT(num_ops <= (size_t)(op - ops));
-  error = grpc_call_start_batch(c, ops, num_ops, tag(1), NULL);
+  error = grpc_call_start_batch(c, ops, num_ops, tag(1), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   CQ_EXPECT_COMPLETION(cqv, tag(1), 1);
@@ -156,7 +156,7 @@ static void test_invoke_simple_request(grpc_end2end_test_config config,
                                        size_t num_ops) {
   grpc_end2end_test_fixture f;
 
-  f = begin_test(config, "test_invoke_simple_request", NULL, NULL);
+  f = begin_test(config, "test_invoke_simple_request", nullptr, nullptr);
   simple_request_body(config, f, num_ops);
   end_test(&f);
   config.tear_down_data(&f);
diff --git a/test/core/end2end/tests/network_status_change.cc b/test/core/end2end/tests/network_status_change.cc
index 088563cb2c..7d0318fda6 100644
--- a/test/core/end2end/tests/network_status_change.cc
+++ b/test/core/end2end/tests/network_status_change.cc
@@ -56,7 +56,7 @@ static gpr_timespec five_seconds_from_now(void) {
 static void drain_cq(grpc_completion_queue* cq) {
   grpc_event ev;
   do {
-    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), NULL);
+    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), nullptr);
   } while (ev.type != GRPC_QUEUE_SHUTDOWN);
 }
 
@@ -65,16 +65,16 @@ static void shutdown_server(grpc_end2end_test_fixture* f) {
   grpc_server_shutdown_and_notify(f->server, f->shutdown_cq, tag(1000));
   GPR_ASSERT(grpc_completion_queue_pluck(f->shutdown_cq, tag(1000),
                                          grpc_timeout_seconds_to_deadline(5),
-                                         NULL)
+                                         nullptr)
                  .type == GRPC_OP_COMPLETE);
   grpc_server_destroy(f->server);
-  f->server = NULL;
+  f->server = nullptr;
 }
 
 static void shutdown_client(grpc_end2end_test_fixture* f) {
   if (!f->client) return;
   grpc_channel_destroy(f->client);
-  f->client = NULL;
+  f->client = nullptr;
 }
 
 static void end_test(grpc_end2end_test_fixture* f) {
@@ -96,14 +96,14 @@ static void test_invoke_network_status_change(grpc_end2end_test_config config) {
   grpc_byte_buffer* request_payload =
       grpc_raw_byte_buffer_create(&request_payload_slice, 1);
   grpc_end2end_test_fixture f =
-      begin_test(config, "test_invoke_request_with_payload", NULL, NULL);
+      begin_test(config, "test_invoke_request_with_payload", nullptr, nullptr);
   cq_verifier* cqv = cq_verifier_create(f.cq);
   grpc_op ops[6];
   grpc_op* op;
   grpc_metadata_array initial_metadata_recv;
   grpc_metadata_array trailing_metadata_recv;
   grpc_metadata_array request_metadata_recv;
-  grpc_byte_buffer* request_payload_recv = NULL;
+  grpc_byte_buffer* request_payload_recv = nullptr;
   grpc_call_details call_details;
   grpc_status_code status;
   grpc_call_error error;
@@ -112,10 +112,10 @@ static void test_invoke_network_status_change(grpc_end2end_test_config config) {
 
   gpr_timespec deadline = five_seconds_from_now();
   c = grpc_channel_create_call(
-      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+      f.client, nullptr, GRPC_PROPAGATE_DEFAULTS, f.cq,
       grpc_slice_from_static_string("/foo"),
       get_host_override_slice("foo.test.google.fr:1234", config), deadline,
-      NULL);
+      nullptr);
   GPR_ASSERT(c);
 
   grpc_metadata_array_init(&initial_metadata_recv);
@@ -128,30 +128,30 @@ static void test_invoke_network_status_change(grpc_end2end_test_config config) {
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
   op->data.send_initial_metadata.count = 0;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_MESSAGE;
   op->data.send_message.send_message = request_payload;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_CLOSE_FROM_CLIENT;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_INITIAL_METADATA;
   op->data.recv_initial_metadata.recv_initial_metadata = &initial_metadata_recv;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_STATUS_ON_CLIENT;
   op->data.recv_status_on_client.trailing_metadata = &trailing_metadata_recv;
   op->data.recv_status_on_client.status = &status;
   op->data.recv_status_on_client.status_details = &details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), NULL);
+  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   GPR_ASSERT(GRPC_CALL_OK == grpc_server_request_call(
@@ -164,14 +164,14 @@ static void test_invoke_network_status_change(grpc_end2end_test_config config) {
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
   op->data.send_initial_metadata.count = 0;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_MESSAGE;
   op->data.recv_message.recv_message = &request_payload_recv;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(102), NULL);
+  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(102), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   CQ_EXPECT_COMPLETION(cqv, tag(102), 1);
@@ -184,7 +184,7 @@ static void test_invoke_network_status_change(grpc_end2end_test_config config) {
   op->op = GRPC_OP_RECV_CLOSE_ON_SERVER;
   op->data.recv_close_on_server.cancelled = &was_cancelled;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_STATUS_FROM_SERVER;
   op->data.send_status_from_server.trailing_metadata_count = 0;
@@ -192,9 +192,9 @@ static void test_invoke_network_status_change(grpc_end2end_test_config config) {
   grpc_slice status_details = grpc_slice_from_static_string("xyz");
   op->data.send_status_from_server.status_details = &status_details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(103), NULL);
+  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(103), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   CQ_EXPECT_COMPLETION(cqv, tag(103), 1);
diff --git a/test/core/end2end/tests/no_logging.cc b/test/core/end2end/tests/no_logging.cc
index 1a7b57cd84..55d211c44a 100644
--- a/test/core/end2end/tests/no_logging.cc
+++ b/test/core/end2end/tests/no_logging.cc
@@ -39,7 +39,7 @@ static void* tag(intptr_t t) { return (void*)t; }
 extern "C" void gpr_default_log(gpr_log_func_args* args);
 
 static void test_no_log(gpr_log_func_args* args) {
-  char* message = NULL;
+  char* message = nullptr;
   gpr_asprintf(&message, "Unwanted log: %s", args->message);
   args->message = message;
   gpr_default_log(args);
@@ -83,7 +83,7 @@ static gpr_timespec five_seconds_from_now(void) {
 static void drain_cq(grpc_completion_queue* cq) {
   grpc_event ev;
   do {
-    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), NULL);
+    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), nullptr);
   } while (ev.type != GRPC_QUEUE_SHUTDOWN);
 }
 
@@ -92,16 +92,16 @@ static void shutdown_server(grpc_end2end_test_fixture* f) {
   grpc_server_shutdown_and_notify(f->server, f->shutdown_cq, tag(1000));
   GPR_ASSERT(grpc_completion_queue_pluck(f->shutdown_cq, tag(1000),
                                          grpc_timeout_seconds_to_deadline(5),
-                                         NULL)
+                                         nullptr)
                  .type == GRPC_OP_COMPLETE);
   grpc_server_destroy(f->server);
-  f->server = NULL;
+  f->server = nullptr;
 }
 
 static void shutdown_client(grpc_end2end_test_fixture* f) {
   if (!f->client) return;
   grpc_channel_destroy(f->client);
-  f->client = NULL;
+  f->client = nullptr;
 }
 
 static void end_test(grpc_end2end_test_fixture* f) {
@@ -133,14 +133,14 @@ static void simple_request_body(grpc_end2end_test_config config,
 
   gpr_timespec deadline = five_seconds_from_now();
   c = grpc_channel_create_call(
-      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+      f.client, nullptr, GRPC_PROPAGATE_DEFAULTS, f.cq,
       grpc_slice_from_static_string("/foo"),
       get_host_override_slice("foo.test.google.fr:1234", config), deadline,
-      NULL);
+      nullptr);
   GPR_ASSERT(c);
 
   peer = grpc_call_get_peer(c);
-  GPR_ASSERT(peer != NULL);
+  GPR_ASSERT(peer != nullptr);
   gpr_free(peer);
 
   grpc_metadata_array_init(&initial_metadata_recv);
@@ -153,25 +153,25 @@ static void simple_request_body(grpc_end2end_test_config config,
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
   op->data.send_initial_metadata.count = 0;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_CLOSE_FROM_CLIENT;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_INITIAL_METADATA;
   op->data.recv_initial_metadata.recv_initial_metadata = &initial_metadata_recv;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_STATUS_ON_CLIENT;
   op->data.recv_status_on_client.trailing_metadata = &trailing_metadata_recv;
   op->data.recv_status_on_client.status = &status;
   op->data.recv_status_on_client.status_details = &details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), NULL);
+  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   error =
@@ -182,10 +182,10 @@ static void simple_request_body(grpc_end2end_test_config config,
   cq_verify(cqv);
 
   peer = grpc_call_get_peer(s);
-  GPR_ASSERT(peer != NULL);
+  GPR_ASSERT(peer != nullptr);
   gpr_free(peer);
   peer = grpc_call_get_peer(c);
-  GPR_ASSERT(peer != NULL);
+  GPR_ASSERT(peer != nullptr);
   gpr_free(peer);
 
   memset(ops, 0, sizeof(ops));
@@ -193,7 +193,7 @@ static void simple_request_body(grpc_end2end_test_config config,
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
   op->data.send_initial_metadata.count = 0;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_STATUS_FROM_SERVER;
   op->data.send_status_from_server.trailing_metadata_count = 0;
@@ -201,14 +201,14 @@ static void simple_request_body(grpc_end2end_test_config config,
   grpc_slice status_details = grpc_slice_from_static_string("xyz");
   op->data.send_status_from_server.status_details = &status_details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_CLOSE_ON_SERVER;
   op->data.recv_close_on_server.cancelled = &was_cancelled;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(102), NULL);
+  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(102), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   CQ_EXPECT_COMPLETION(cqv, tag(102), 1);
@@ -239,7 +239,7 @@ static void test_invoke_simple_request(grpc_end2end_test_config config) {
   grpc_end2end_test_fixture f;
 
   f = begin_test(config, "test_invoke_simple_request_with_no_error_logging",
-                 NULL, NULL);
+                 nullptr, nullptr);
   simple_request_body(config, f);
   end_test(&f);
   config.tear_down_data(&f);
@@ -249,7 +249,7 @@ static void test_invoke_10_simple_requests(grpc_end2end_test_config config) {
   int i;
   grpc_end2end_test_fixture f =
       begin_test(config, "test_invoke_10_simple_requests_with_no_error_logging",
-                 NULL, NULL);
+                 nullptr, nullptr);
   for (i = 0; i < 10; i++) {
     simple_request_body(config, f);
     gpr_log(GPR_INFO, "Passed simple request %d", i);
@@ -273,7 +273,7 @@ static void test_no_error_logging_in_entire_process(
 static void test_no_logging_in_one_request(grpc_end2end_test_config config) {
   int i;
   grpc_end2end_test_fixture f =
-      begin_test(config, "test_no_logging_in_last_request", NULL, NULL);
+      begin_test(config, "test_no_logging_in_last_request", nullptr, nullptr);
   for (i = 0; i < 10; i++) {
     simple_request_body(config, f);
   }
diff --git a/test/core/end2end/tests/no_op.cc b/test/core/end2end/tests/no_op.cc
index 98cf5eb9dc..18c2367ac4 100644
--- a/test/core/end2end/tests/no_op.cc
+++ b/test/core/end2end/tests/no_op.cc
@@ -53,7 +53,7 @@ static gpr_timespec five_seconds_from_now(void) {
 static void drain_cq(grpc_completion_queue* cq) {
   grpc_event ev;
   do {
-    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), NULL);
+    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), nullptr);
   } while (ev.type != GRPC_QUEUE_SHUTDOWN);
 }
 
@@ -62,16 +62,16 @@ static void shutdown_server(grpc_end2end_test_fixture* f) {
   grpc_server_shutdown_and_notify(f->server, f->shutdown_cq, tag(1000));
   GPR_ASSERT(grpc_completion_queue_pluck(f->shutdown_cq, tag(1000),
                                          grpc_timeout_seconds_to_deadline(5),
-                                         NULL)
+                                         nullptr)
                  .type == GRPC_OP_COMPLETE);
   grpc_server_destroy(f->server);
-  f->server = NULL;
+  f->server = nullptr;
 }
 
 static void shutdown_client(grpc_end2end_test_fixture* f) {
   if (!f->client) return;
   grpc_channel_destroy(f->client);
-  f->client = NULL;
+  f->client = nullptr;
 }
 
 static void end_test(grpc_end2end_test_fixture* f) {
@@ -85,7 +85,7 @@ static void end_test(grpc_end2end_test_fixture* f) {
 }
 
 static void test_no_op(grpc_end2end_test_config config) {
-  grpc_end2end_test_fixture f = begin_test(config, "no-op", NULL, NULL);
+  grpc_end2end_test_fixture f = begin_test(config, "no-op", nullptr, nullptr);
   end_test(&f);
   config.tear_down_data(&f);
 }
diff --git a/test/core/end2end/tests/payload.cc b/test/core/end2end/tests/payload.cc
index 0ff9461a47..2e9513b9cb 100644
--- a/test/core/end2end/tests/payload.cc
+++ b/test/core/end2end/tests/payload.cc
@@ -53,7 +53,7 @@ static gpr_timespec five_seconds_from_now(void) {
 static void drain_cq(grpc_completion_queue* cq) {
   grpc_event ev;
   do {
-    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), NULL);
+    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), nullptr);
   } while (ev.type != GRPC_QUEUE_SHUTDOWN);
 }
 
@@ -62,16 +62,16 @@ static void shutdown_server(grpc_end2end_test_fixture* f) {
   grpc_server_shutdown_and_notify(f->server, f->shutdown_cq, tag(1000));
   GPR_ASSERT(grpc_completion_queue_pluck(f->shutdown_cq, tag(1000),
                                          grpc_timeout_seconds_to_deadline(5),
-                                         NULL)
+                                         nullptr)
                  .type == GRPC_OP_COMPLETE);
   grpc_server_destroy(f->server);
-  f->server = NULL;
+  f->server = nullptr;
 }
 
 static void shutdown_client(grpc_end2end_test_fixture* f) {
   if (!f->client) return;
   grpc_channel_destroy(f->client);
-  f->client = NULL;
+  f->client = nullptr;
 }
 
 static void end_test(grpc_end2end_test_fixture* f) {
@@ -121,8 +121,8 @@ static void request_response_with_payload(grpc_end2end_test_config config,
   grpc_metadata_array initial_metadata_recv;
   grpc_metadata_array trailing_metadata_recv;
   grpc_metadata_array request_metadata_recv;
-  grpc_byte_buffer* request_payload_recv = NULL;
-  grpc_byte_buffer* response_payload_recv = NULL;
+  grpc_byte_buffer* request_payload_recv = nullptr;
+  grpc_byte_buffer* response_payload_recv = nullptr;
   grpc_call_details call_details;
   grpc_status_code status;
   grpc_call_error error;
@@ -131,10 +131,10 @@ static void request_response_with_payload(grpc_end2end_test_config config,
 
   gpr_timespec deadline = n_seconds_from_now(60);
   c = grpc_channel_create_call(
-      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+      f.client, nullptr, GRPC_PROPAGATE_DEFAULTS, f.cq,
       grpc_slice_from_static_string("/foo"),
       get_host_override_slice("foo.test.google.fr:1234", config), deadline,
-      NULL);
+      nullptr);
   GPR_ASSERT(c);
 
   grpc_metadata_array_init(&initial_metadata_recv);
@@ -147,35 +147,35 @@ static void request_response_with_payload(grpc_end2end_test_config config,
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
   op->data.send_initial_metadata.count = 0;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_MESSAGE;
   op->data.send_message.send_message = request_payload;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_CLOSE_FROM_CLIENT;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_INITIAL_METADATA;
   op->data.recv_initial_metadata.recv_initial_metadata = &initial_metadata_recv;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_MESSAGE;
   op->data.recv_message.recv_message = &response_payload_recv;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_STATUS_ON_CLIENT;
   op->data.recv_status_on_client.trailing_metadata = &trailing_metadata_recv;
   op->data.recv_status_on_client.status = &status;
   op->data.recv_status_on_client.status_details = &details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), NULL);
+  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   error =
@@ -190,14 +190,14 @@ static void request_response_with_payload(grpc_end2end_test_config config,
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
   op->data.send_initial_metadata.count = 0;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_MESSAGE;
   op->data.recv_message.recv_message = &request_payload_recv;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(102), NULL);
+  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(102), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   CQ_EXPECT_COMPLETION(cqv, tag(102), 1);
@@ -208,12 +208,12 @@ static void request_response_with_payload(grpc_end2end_test_config config,
   op->op = GRPC_OP_RECV_CLOSE_ON_SERVER;
   op->data.recv_close_on_server.cancelled = &was_cancelled;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_MESSAGE;
   op->data.send_message.send_message = response_payload;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_STATUS_FROM_SERVER;
   op->data.send_status_from_server.trailing_metadata_count = 0;
@@ -221,9 +221,9 @@ static void request_response_with_payload(grpc_end2end_test_config config,
   grpc_slice status_details = grpc_slice_from_static_string("xyz");
   op->data.send_status_from_server.status_details = &status_details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(103), NULL);
+  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(103), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   CQ_EXPECT_COMPLETION(cqv, tag(103), 1);
@@ -262,7 +262,7 @@ static void request_response_with_payload(grpc_end2end_test_config config,
 static void test_invoke_request_response_with_payload(
     grpc_end2end_test_config config) {
   grpc_end2end_test_fixture f = begin_test(
-      config, "test_invoke_request_response_with_payload", NULL, NULL);
+      config, "test_invoke_request_response_with_payload", nullptr, nullptr);
   request_response_with_payload(config, f);
   end_test(&f);
   config.tear_down_data(&f);
@@ -272,7 +272,7 @@ static void test_invoke_10_request_response_with_payload(
     grpc_end2end_test_config config) {
   int i;
   grpc_end2end_test_fixture f = begin_test(
-      config, "test_invoke_10_request_response_with_payload", NULL, NULL);
+      config, "test_invoke_10_request_response_with_payload", nullptr, nullptr);
   for (i = 0; i < 10; i++) {
     request_response_with_payload(config, f);
   }
diff --git a/test/core/end2end/tests/ping.cc b/test/core/end2end/tests/ping.cc
index 88f62c0a2b..725a425fbf 100644
--- a/test/core/end2end/tests/ping.cc
+++ b/test/core/end2end/tests/ping.cc
@@ -32,7 +32,7 @@ static void* tag(intptr_t t) { return (void*)t; }
 
 static void test_ping(grpc_end2end_test_config config,
                       int min_time_between_pings_ms) {
-  grpc_end2end_test_fixture f = config.create_fixture(NULL, NULL);
+  grpc_end2end_test_fixture f = config.create_fixture(nullptr, nullptr);
   cq_verifier* cqv = cq_verifier_create(f.cq);
   grpc_connectivity_state state = GRPC_CHANNEL_IDLE;
   int i;
@@ -62,7 +62,7 @@ static void test_ping(grpc_end2end_test_config config,
   config.init_client(&f, &client_args);
   config.init_server(&f, &server_args);
 
-  grpc_channel_ping(f.client, f.cq, tag(0), NULL);
+  grpc_channel_ping(f.client, f.cq, tag(0), nullptr);
   CQ_EXPECT_COMPLETION(cqv, tag(0), 0);
 
   /* check that we're still in idle, and start connecting */
@@ -86,7 +86,7 @@ static void test_ping(grpc_end2end_test_config config,
   }
 
   for (i = 1; i <= PING_NUM; i++) {
-    grpc_channel_ping(f.client, f.cq, tag(i), NULL);
+    grpc_channel_ping(f.client, f.cq, tag(i), nullptr);
     CQ_EXPECT_COMPLETION(cqv, tag(i), 1);
     cq_verify(cqv);
   }
diff --git a/test/core/end2end/tests/ping_pong_streaming.cc b/test/core/end2end/tests/ping_pong_streaming.cc
index 3c2e76b9f9..47aebe52a1 100644
--- a/test/core/end2end/tests/ping_pong_streaming.cc
+++ b/test/core/end2end/tests/ping_pong_streaming.cc
@@ -53,7 +53,7 @@ static gpr_timespec five_seconds_from_now(void) {
 static void drain_cq(grpc_completion_queue* cq) {
   grpc_event ev;
   do {
-    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), NULL);
+    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), nullptr);
   } while (ev.type != GRPC_QUEUE_SHUTDOWN);
 }
 
@@ -62,16 +62,16 @@ static void shutdown_server(grpc_end2end_test_fixture* f) {
   grpc_server_shutdown_and_notify(f->server, f->shutdown_cq, tag(1000));
   GPR_ASSERT(grpc_completion_queue_pluck(f->shutdown_cq, tag(1000),
                                          grpc_timeout_seconds_to_deadline(5),
-                                         NULL)
+                                         nullptr)
                  .type == GRPC_OP_COMPLETE);
   grpc_server_destroy(f->server);
-  f->server = NULL;
+  f->server = nullptr;
 }
 
 static void shutdown_client(grpc_end2end_test_fixture* f) {
   if (!f->client) return;
   grpc_channel_destroy(f->client);
-  f->client = NULL;
+  f->client = nullptr;
 }
 
 static void end_test(grpc_end2end_test_fixture* f) {
@@ -88,7 +88,7 @@ static void end_test(grpc_end2end_test_fixture* f) {
 static void test_pingpong_streaming(grpc_end2end_test_config config,
                                     int messages) {
   grpc_end2end_test_fixture f =
-      begin_test(config, "test_pingpong_streaming", NULL, NULL);
+      begin_test(config, "test_pingpong_streaming", nullptr, nullptr);
   grpc_call* c;
   grpc_call* s;
   cq_verifier* cqv = cq_verifier_create(f.cq);
@@ -114,10 +114,10 @@ static void test_pingpong_streaming(grpc_end2end_test_config config,
 
   gpr_timespec deadline = five_seconds_from_now();
   c = grpc_channel_create_call(
-      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+      f.client, nullptr, GRPC_PROPAGATE_DEFAULTS, f.cq,
       grpc_slice_from_static_string("/foo"),
       get_host_override_slice("foo.test.google.fr:1234", config), deadline,
-      NULL);
+      nullptr);
   GPR_ASSERT(c);
 
   grpc_metadata_array_init(&initial_metadata_recv);
@@ -130,21 +130,21 @@ static void test_pingpong_streaming(grpc_end2end_test_config config,
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
   op->data.send_initial_metadata.count = 0;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_INITIAL_METADATA;
   op->data.recv_initial_metadata.recv_initial_metadata = &initial_metadata_recv;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_STATUS_ON_CLIENT;
   op->data.recv_status_on_client.trailing_metadata = &trailing_metadata_recv;
   op->data.recv_status_on_client.status = &status;
   op->data.recv_status_on_client.status_details = &details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), NULL);
+  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   error =
@@ -159,14 +159,14 @@ static void test_pingpong_streaming(grpc_end2end_test_config config,
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
   op->data.send_initial_metadata.count = 0;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_CLOSE_ON_SERVER;
   op->data.recv_close_on_server.cancelled = &was_cancelled;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(101), NULL);
+  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(101), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   for (i = 0; i < messages; i++) {
@@ -178,14 +178,14 @@ static void test_pingpong_streaming(grpc_end2end_test_config config,
     op->op = GRPC_OP_SEND_MESSAGE;
     op->data.send_message.send_message = request_payload;
     op->flags = 0;
-    op->reserved = NULL;
+    op->reserved = nullptr;
     op++;
     op->op = GRPC_OP_RECV_MESSAGE;
     op->data.recv_message.recv_message = &response_payload_recv;
     op->flags = 0;
-    op->reserved = NULL;
+    op->reserved = nullptr;
     op++;
-    error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(2), NULL);
+    error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(2), nullptr);
     GPR_ASSERT(GRPC_CALL_OK == error);
 
     memset(ops, 0, sizeof(ops));
@@ -193,9 +193,9 @@ static void test_pingpong_streaming(grpc_end2end_test_config config,
     op->op = GRPC_OP_RECV_MESSAGE;
     op->data.recv_message.recv_message = &request_payload_recv;
     op->flags = 0;
-    op->reserved = NULL;
+    op->reserved = nullptr;
     op++;
-    error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(102), NULL);
+    error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(102), nullptr);
     GPR_ASSERT(GRPC_CALL_OK == error);
     CQ_EXPECT_COMPLETION(cqv, tag(102), 1);
     cq_verify(cqv);
@@ -205,9 +205,9 @@ static void test_pingpong_streaming(grpc_end2end_test_config config,
     op->op = GRPC_OP_SEND_MESSAGE;
     op->data.send_message.send_message = response_payload;
     op->flags = 0;
-    op->reserved = NULL;
+    op->reserved = nullptr;
     op++;
-    error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(103), NULL);
+    error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(103), nullptr);
     GPR_ASSERT(GRPC_CALL_OK == error);
     CQ_EXPECT_COMPLETION(cqv, tag(103), 1);
     CQ_EXPECT_COMPLETION(cqv, tag(2), 1);
@@ -226,9 +226,9 @@ static void test_pingpong_streaming(grpc_end2end_test_config config,
   op = ops;
   op->op = GRPC_OP_SEND_CLOSE_FROM_CLIENT;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(3), NULL);
+  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(3), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   memset(ops, 0, sizeof(ops));
@@ -239,9 +239,9 @@ static void test_pingpong_streaming(grpc_end2end_test_config config,
   grpc_slice status_details = grpc_slice_from_static_string("xyz");
   op->data.send_status_from_server.status_details = &status_details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(104), NULL);
+  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(104), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   CQ_EXPECT_COMPLETION(cqv, tag(1), 1);
diff --git a/test/core/end2end/tests/proxy_auth.cc b/test/core/end2end/tests/proxy_auth.cc
index d5dce7c6de..e4b91ab879 100644
--- a/test/core/end2end/tests/proxy_auth.cc
+++ b/test/core/end2end/tests/proxy_auth.cc
@@ -60,7 +60,7 @@ static gpr_timespec five_seconds_from_now(void) {
 static void drain_cq(grpc_completion_queue* cq) {
   grpc_event ev;
   do {
-    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), NULL);
+    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), nullptr);
   } while (ev.type != GRPC_QUEUE_SHUTDOWN);
 }
 
@@ -69,16 +69,16 @@ static void shutdown_server(grpc_end2end_test_fixture* f) {
   grpc_server_shutdown_and_notify(f->server, f->shutdown_cq, tag(1000));
   GPR_ASSERT(grpc_completion_queue_pluck(f->shutdown_cq, tag(1000),
                                          grpc_timeout_seconds_to_deadline(5),
-                                         NULL)
+                                         nullptr)
                  .type == GRPC_OP_COMPLETE);
   grpc_server_destroy(f->server);
-  f->server = NULL;
+  f->server = nullptr;
 }
 
 static void shutdown_client(grpc_end2end_test_fixture* f) {
   if (!f->client) return;
   grpc_channel_destroy(f->client);
-  f->client = NULL;
+  f->client = nullptr;
 }
 
 static void end_test(grpc_end2end_test_fixture* f) {
@@ -110,14 +110,14 @@ static void simple_request_body(grpc_end2end_test_config config,
 
   gpr_timespec deadline = five_seconds_from_now();
   c = grpc_channel_create_call(
-      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+      f.client, nullptr, GRPC_PROPAGATE_DEFAULTS, f.cq,
       grpc_slice_from_static_string("/foo"),
       get_host_override_slice("foo.test.google.fr:1234", config), deadline,
-      NULL);
+      nullptr);
   GPR_ASSERT(c);
 
   peer = grpc_call_get_peer(c);
-  GPR_ASSERT(peer != NULL);
+  GPR_ASSERT(peer != nullptr);
   gpr_log(GPR_DEBUG, "client_peer_before_call=%s", peer);
   gpr_free(peer);
 
@@ -131,25 +131,25 @@ static void simple_request_body(grpc_end2end_test_config config,
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
   op->data.send_initial_metadata.count = 0;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_CLOSE_FROM_CLIENT;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_INITIAL_METADATA;
   op->data.recv_initial_metadata.recv_initial_metadata = &initial_metadata_recv;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_STATUS_ON_CLIENT;
   op->data.recv_status_on_client.trailing_metadata = &trailing_metadata_recv;
   op->data.recv_status_on_client.status = &status;
   op->data.recv_status_on_client.status_details = &details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), NULL);
+  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   error =
@@ -160,11 +160,11 @@ static void simple_request_body(grpc_end2end_test_config config,
   cq_verify(cqv);
 
   peer = grpc_call_get_peer(s);
-  GPR_ASSERT(peer != NULL);
+  GPR_ASSERT(peer != nullptr);
   gpr_log(GPR_DEBUG, "server_peer=%s", peer);
   gpr_free(peer);
   peer = grpc_call_get_peer(c);
-  GPR_ASSERT(peer != NULL);
+  GPR_ASSERT(peer != nullptr);
   gpr_log(GPR_DEBUG, "client_peer=%s", peer);
   gpr_free(peer);
 
@@ -173,7 +173,7 @@ static void simple_request_body(grpc_end2end_test_config config,
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
   op->data.send_initial_metadata.count = 0;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_STATUS_FROM_SERVER;
   op->data.send_status_from_server.trailing_metadata_count = 0;
@@ -181,14 +181,14 @@ static void simple_request_body(grpc_end2end_test_config config,
   grpc_slice status_details = grpc_slice_from_static_string("xyz");
   op->data.send_status_from_server.status_details = &status_details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_CLOSE_ON_SERVER;
   op->data.recv_close_on_server.cancelled = &was_cancelled;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(102), NULL);
+  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(102), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   CQ_EXPECT_COMPLETION(cqv, tag(102), 1);
@@ -223,7 +223,7 @@ static void test_invoke_proxy_auth(grpc_end2end_test_config config) {
   client_arg.value.string = const_cast<char*>(GRPC_TEST_HTTP_PROXY_AUTH_CREDS);
   grpc_channel_args client_args = {1, &client_arg};
   grpc_end2end_test_fixture f =
-      begin_test(config, "test_invoke_proxy_auth", &client_args, NULL);
+      begin_test(config, "test_invoke_proxy_auth", &client_args, nullptr);
   simple_request_body(config, f);
   end_test(&f);
   config.tear_down_data(&f);
diff --git a/test/core/end2end/tests/registered_call.cc b/test/core/end2end/tests/registered_call.cc
index b43ca04766..440d817cf1 100644
--- a/test/core/end2end/tests/registered_call.cc
+++ b/test/core/end2end/tests/registered_call.cc
@@ -55,7 +55,7 @@ static gpr_timespec five_seconds_from_now(void) {
 static void drain_cq(grpc_completion_queue* cq) {
   grpc_event ev;
   do {
-    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), NULL);
+    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), nullptr);
   } while (ev.type != GRPC_QUEUE_SHUTDOWN);
 }
 
@@ -64,16 +64,16 @@ static void shutdown_server(grpc_end2end_test_fixture* f) {
   grpc_server_shutdown_and_notify(f->server, f->shutdown_cq, tag(1000));
   GPR_ASSERT(grpc_completion_queue_pluck(f->shutdown_cq, tag(1000),
                                          grpc_timeout_seconds_to_deadline(5),
-                                         NULL)
+                                         nullptr)
                  .type == GRPC_OP_COMPLETE);
   grpc_server_destroy(f->server);
-  f->server = NULL;
+  f->server = nullptr;
 }
 
 static void shutdown_client(grpc_end2end_test_fixture* f) {
   if (!f->client) return;
   grpc_channel_destroy(f->client);
-  f->client = NULL;
+  f->client = nullptr;
 }
 
 static void end_test(grpc_end2end_test_fixture* f) {
@@ -104,7 +104,7 @@ static void simple_request_body(grpc_end2end_test_config config,
 
   gpr_timespec deadline = five_seconds_from_now();
   c = grpc_channel_create_registered_call(
-      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq, rc, deadline, NULL);
+      f.client, nullptr, GRPC_PROPAGATE_DEFAULTS, f.cq, rc, deadline, nullptr);
   GPR_ASSERT(c);
 
   grpc_metadata_array_init(&initial_metadata_recv);
@@ -117,25 +117,25 @@ static void simple_request_body(grpc_end2end_test_config config,
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
   op->data.send_initial_metadata.count = 0;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_CLOSE_FROM_CLIENT;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_INITIAL_METADATA;
   op->data.recv_initial_metadata.recv_initial_metadata = &initial_metadata_recv;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_STATUS_ON_CLIENT;
   op->data.recv_status_on_client.trailing_metadata = &trailing_metadata_recv;
   op->data.recv_status_on_client.status = &status;
   op->data.recv_status_on_client.status_details = &details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), NULL);
+  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   error =
@@ -150,7 +150,7 @@ static void simple_request_body(grpc_end2end_test_config config,
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
   op->data.send_initial_metadata.count = 0;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_STATUS_FROM_SERVER;
   op->data.send_status_from_server.trailing_metadata_count = 0;
@@ -158,14 +158,14 @@ static void simple_request_body(grpc_end2end_test_config config,
   grpc_slice status_details = grpc_slice_from_static_string("xyz");
   op->data.send_status_from_server.status_details = &status_details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_CLOSE_ON_SERVER;
   op->data.recv_close_on_server.cancelled = &was_cancelled;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(102), NULL);
+  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(102), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   CQ_EXPECT_COMPLETION(cqv, tag(102), 1);
@@ -193,10 +193,10 @@ static void simple_request_body(grpc_end2end_test_config config,
 
 static void test_invoke_simple_request(grpc_end2end_test_config config) {
   grpc_end2end_test_fixture f =
-      begin_test(config, "test_invoke_simple_request", NULL, NULL);
+      begin_test(config, "test_invoke_simple_request", nullptr, nullptr);
   void* rc = grpc_channel_register_call(
       f.client, "/foo",
-      get_host_override_string("foo.test.google.fr:1234", config), NULL);
+      get_host_override_string("foo.test.google.fr:1234", config), nullptr);
 
   simple_request_body(config, f, rc);
   end_test(&f);
@@ -206,10 +206,10 @@ static void test_invoke_simple_request(grpc_end2end_test_config config) {
 static void test_invoke_10_simple_requests(grpc_end2end_test_config config) {
   int i;
   grpc_end2end_test_fixture f =
-      begin_test(config, "test_invoke_10_simple_requests", NULL, NULL);
+      begin_test(config, "test_invoke_10_simple_requests", nullptr, nullptr);
   void* rc = grpc_channel_register_call(
       f.client, "/foo",
-      get_host_override_string("foo.test.google.fr:1234", config), NULL);
+      get_host_override_string("foo.test.google.fr:1234", config), nullptr);
 
   for (i = 0; i < 10; i++) {
     simple_request_body(config, f, rc);
diff --git a/test/core/end2end/tests/request_with_flags.cc b/test/core/end2end/tests/request_with_flags.cc
index 77c931844c..984d8b10f1 100644
--- a/test/core/end2end/tests/request_with_flags.cc
+++ b/test/core/end2end/tests/request_with_flags.cc
@@ -54,7 +54,7 @@ static gpr_timespec five_seconds_from_now(void) {
 static void drain_cq(grpc_completion_queue* cq) {
   grpc_event ev;
   do {
-    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), NULL);
+    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), nullptr);
   } while (ev.type != GRPC_QUEUE_SHUTDOWN);
 }
 
@@ -63,16 +63,16 @@ static void shutdown_server(grpc_end2end_test_fixture* f) {
   grpc_server_shutdown_and_notify(f->server, f->shutdown_cq, tag(1000));
   GPR_ASSERT(grpc_completion_queue_pluck(f->shutdown_cq, tag(1000),
                                          grpc_timeout_seconds_to_deadline(5),
-                                         NULL)
+                                         nullptr)
                  .type == GRPC_OP_COMPLETE);
   grpc_server_destroy(f->server);
-  f->server = NULL;
+  f->server = nullptr;
 }
 
 static void shutdown_client(grpc_end2end_test_fixture* f) {
   if (!f->client) return;
   grpc_channel_destroy(f->client);
-  f->client = NULL;
+  f->client = nullptr;
 }
 
 static void end_test(grpc_end2end_test_fixture* f) {
@@ -94,14 +94,14 @@ static void test_invoke_request_with_flags(
   grpc_byte_buffer* request_payload =
       grpc_raw_byte_buffer_create(&request_payload_slice, 1);
   grpc_end2end_test_fixture f =
-      begin_test(config, "test_invoke_request_with_flags", NULL, NULL);
+      begin_test(config, "test_invoke_request_with_flags", nullptr, nullptr);
   cq_verifier* cqv = cq_verifier_create(f.cq);
   grpc_op ops[6];
   grpc_op* op;
   grpc_metadata_array initial_metadata_recv;
   grpc_metadata_array trailing_metadata_recv;
   grpc_metadata_array request_metadata_recv;
-  grpc_byte_buffer* request_payload_recv = NULL;
+  grpc_byte_buffer* request_payload_recv = nullptr;
   grpc_call_details call_details;
   grpc_status_code status;
   grpc_call_error error;
@@ -110,10 +110,10 @@ static void test_invoke_request_with_flags(
 
   gpr_timespec deadline = five_seconds_from_now();
   c = grpc_channel_create_call(
-      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+      f.client, nullptr, GRPC_PROPAGATE_DEFAULTS, f.cq,
       grpc_slice_from_static_string("/foo"),
       get_host_override_slice("foo.test.google.fr:1234", config), deadline,
-      NULL);
+      nullptr);
   GPR_ASSERT(c);
 
   grpc_metadata_array_init(&initial_metadata_recv);
@@ -126,31 +126,31 @@ static void test_invoke_request_with_flags(
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
   op->data.send_initial_metadata.count = 0;
   op->flags = flags_for_op[op->op];
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_MESSAGE;
   op->data.send_message.send_message = request_payload;
   op->flags = flags_for_op[op->op];
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_CLOSE_FROM_CLIENT;
   op->flags = flags_for_op[op->op];
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_INITIAL_METADATA;
   op->data.recv_initial_metadata.recv_initial_metadata = &initial_metadata_recv;
   op->flags = flags_for_op[op->op];
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_STATUS_ON_CLIENT;
   op->data.recv_status_on_client.trailing_metadata = &trailing_metadata_recv;
   op->data.recv_status_on_client.status = &status;
   op->data.recv_status_on_client.status_details = &details;
   op->flags = flags_for_op[op->op];
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   expectation = call_start_batch_expected_result;
-  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), NULL);
+  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), nullptr);
   GPR_ASSERT(expectation == error);
 
   if (expectation == GRPC_CALL_OK) {
diff --git a/test/core/end2end/tests/request_with_payload.cc b/test/core/end2end/tests/request_with_payload.cc
index 946144239c..b3b9ee5726 100644
--- a/test/core/end2end/tests/request_with_payload.cc
+++ b/test/core/end2end/tests/request_with_payload.cc
@@ -53,7 +53,7 @@ static gpr_timespec five_seconds_from_now(void) {
 static void drain_cq(grpc_completion_queue* cq) {
   grpc_event ev;
   do {
-    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), NULL);
+    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), nullptr);
   } while (ev.type != GRPC_QUEUE_SHUTDOWN);
 }
 
@@ -62,16 +62,16 @@ static void shutdown_server(grpc_end2end_test_fixture* f) {
   grpc_server_shutdown_and_notify(f->server, f->shutdown_cq, tag(1000));
   GPR_ASSERT(grpc_completion_queue_pluck(f->shutdown_cq, tag(1000),
                                          grpc_timeout_seconds_to_deadline(5),
-                                         NULL)
+                                         nullptr)
                  .type == GRPC_OP_COMPLETE);
   grpc_server_destroy(f->server);
-  f->server = NULL;
+  f->server = nullptr;
 }
 
 static void shutdown_client(grpc_end2end_test_fixture* f) {
   if (!f->client) return;
   grpc_channel_destroy(f->client);
-  f->client = NULL;
+  f->client = nullptr;
 }
 
 static void end_test(grpc_end2end_test_fixture* f) {
@@ -93,14 +93,14 @@ static void test_invoke_request_with_payload(grpc_end2end_test_config config) {
   grpc_byte_buffer* request_payload =
       grpc_raw_byte_buffer_create(&request_payload_slice, 1);
   grpc_end2end_test_fixture f =
-      begin_test(config, "test_invoke_request_with_payload", NULL, NULL);
+      begin_test(config, "test_invoke_request_with_payload", nullptr, nullptr);
   cq_verifier* cqv = cq_verifier_create(f.cq);
   grpc_op ops[6];
   grpc_op* op;
   grpc_metadata_array initial_metadata_recv;
   grpc_metadata_array trailing_metadata_recv;
   grpc_metadata_array request_metadata_recv;
-  grpc_byte_buffer* request_payload_recv = NULL;
+  grpc_byte_buffer* request_payload_recv = nullptr;
   grpc_call_details call_details;
   grpc_status_code status;
   grpc_call_error error;
@@ -109,10 +109,10 @@ static void test_invoke_request_with_payload(grpc_end2end_test_config config) {
 
   gpr_timespec deadline = five_seconds_from_now();
   c = grpc_channel_create_call(
-      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+      f.client, nullptr, GRPC_PROPAGATE_DEFAULTS, f.cq,
       grpc_slice_from_static_string("/foo"),
       get_host_override_slice("foo.test.google.fr:1234", config), deadline,
-      NULL);
+      nullptr);
   GPR_ASSERT(c);
 
   grpc_metadata_array_init(&initial_metadata_recv);
@@ -125,30 +125,30 @@ static void test_invoke_request_with_payload(grpc_end2end_test_config config) {
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
   op->data.send_initial_metadata.count = 0;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_MESSAGE;
   op->data.send_message.send_message = request_payload;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_CLOSE_FROM_CLIENT;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_INITIAL_METADATA;
   op->data.recv_initial_metadata.recv_initial_metadata = &initial_metadata_recv;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_STATUS_ON_CLIENT;
   op->data.recv_status_on_client.trailing_metadata = &trailing_metadata_recv;
   op->data.recv_status_on_client.status = &status;
   op->data.recv_status_on_client.status_details = &details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), NULL);
+  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   GPR_ASSERT(GRPC_CALL_OK == grpc_server_request_call(
@@ -162,14 +162,14 @@ static void test_invoke_request_with_payload(grpc_end2end_test_config config) {
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
   op->data.send_initial_metadata.count = 0;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_MESSAGE;
   op->data.recv_message.recv_message = &request_payload_recv;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(102), NULL);
+  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(102), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   CQ_EXPECT_COMPLETION(cqv, tag(102), 1);
@@ -180,7 +180,7 @@ static void test_invoke_request_with_payload(grpc_end2end_test_config config) {
   op->op = GRPC_OP_RECV_CLOSE_ON_SERVER;
   op->data.recv_close_on_server.cancelled = &was_cancelled;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_STATUS_FROM_SERVER;
   op->data.send_status_from_server.trailing_metadata_count = 0;
@@ -188,9 +188,9 @@ static void test_invoke_request_with_payload(grpc_end2end_test_config config) {
   grpc_slice status_details = grpc_slice_from_static_string("xyz");
   op->data.send_status_from_server.status_details = &status_details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(103), NULL);
+  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(103), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   CQ_EXPECT_COMPLETION(cqv, tag(103), 1);
diff --git a/test/core/end2end/tests/resource_quota_server.cc b/test/core/end2end/tests/resource_quota_server.cc
index dd00c9843f..0ee014f97d 100644
--- a/test/core/end2end/tests/resource_quota_server.cc
+++ b/test/core/end2end/tests/resource_quota_server.cc
@@ -53,7 +53,7 @@ static gpr_timespec five_seconds_from_now(void) {
 static void drain_cq(grpc_completion_queue* cq) {
   grpc_event ev;
   do {
-    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), NULL);
+    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), nullptr);
   } while (ev.type != GRPC_QUEUE_SHUTDOWN);
 }
 
@@ -62,16 +62,16 @@ static void shutdown_server(grpc_end2end_test_fixture* f) {
   grpc_server_shutdown_and_notify(f->server, f->shutdown_cq, tag(1000));
   GPR_ASSERT(grpc_completion_queue_pluck(f->shutdown_cq, tag(1000),
                                          grpc_timeout_seconds_to_deadline(5),
-                                         NULL)
+                                         nullptr)
                  .type == GRPC_OP_COMPLETE);
   grpc_server_destroy(f->server);
-  f->server = NULL;
+  f->server = nullptr;
 }
 
 static void shutdown_client(grpc_end2end_test_fixture* f) {
   if (!f->client) return;
   grpc_channel_destroy(f->client);
-  f->client = NULL;
+  f->client = nullptr;
 }
 
 static void end_test(grpc_end2end_test_fixture* f) {
@@ -124,7 +124,7 @@ void resource_quota_server(grpc_end2end_test_config config) {
   grpc_channel_args args = {1, &arg};
 
   grpc_end2end_test_fixture f =
-      begin_test(config, "resource_quota_server", NULL, &args);
+      begin_test(config, "resource_quota_server", nullptr, &args);
 
   /* Create large request and response bodies. These are big enough to require
    * multiple round trips to deliver to the peer, and their exact contents of
@@ -170,7 +170,7 @@ void resource_quota_server(grpc_end2end_test_config config) {
     grpc_metadata_array_init(&request_metadata_recv[i]);
     grpc_call_details_init(&call_details[i]);
     request_payload[i] = grpc_raw_byte_buffer_create(&request_payload_slice, 1);
-    request_payload_recv[i] = NULL;
+    request_payload_recv[i] = nullptr;
     was_cancelled[i] = 0;
   }
 
@@ -185,32 +185,32 @@ void resource_quota_server(grpc_end2end_test_config config) {
 
   for (int i = 0; i < NUM_CALLS; i++) {
     client_calls[i] = grpc_channel_create_call(
-        f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+        f.client, nullptr, GRPC_PROPAGATE_DEFAULTS, f.cq,
         grpc_slice_from_static_string("/foo"),
         get_host_override_slice("foo.test.google.fr", config),
-        n_seconds_from_now(60), NULL);
+        n_seconds_from_now(60), nullptr);
 
     memset(ops, 0, sizeof(ops));
     op = ops;
     op->op = GRPC_OP_SEND_INITIAL_METADATA;
     op->data.send_initial_metadata.count = 0;
     op->flags = GRPC_INITIAL_METADATA_WAIT_FOR_READY;
-    op->reserved = NULL;
+    op->reserved = nullptr;
     op++;
     op->op = GRPC_OP_SEND_MESSAGE;
     op->data.send_message.send_message = request_payload[i];
     op->flags = 0;
-    op->reserved = NULL;
+    op->reserved = nullptr;
     op++;
     op->op = GRPC_OP_SEND_CLOSE_FROM_CLIENT;
     op->flags = 0;
-    op->reserved = NULL;
+    op->reserved = nullptr;
     op++;
     op->op = GRPC_OP_RECV_INITIAL_METADATA;
     op->data.recv_initial_metadata.recv_initial_metadata =
         &initial_metadata_recv[i];
     op->flags = 0;
-    op->reserved = NULL;
+    op->reserved = nullptr;
     op++;
     op->op = GRPC_OP_RECV_STATUS_ON_CLIENT;
     op->data.recv_status_on_client.trailing_metadata =
@@ -218,10 +218,10 @@ void resource_quota_server(grpc_end2end_test_config config) {
     op->data.recv_status_on_client.status = &status[i];
     op->data.recv_status_on_client.status_details = &details[i];
     op->flags = 0;
-    op->reserved = NULL;
+    op->reserved = nullptr;
     op++;
     error = grpc_call_start_batch(client_calls[i], ops, (size_t)(op - ops),
-                                  tag(CLIENT_BASE_TAG + i), NULL);
+                                  tag(CLIENT_BASE_TAG + i), nullptr);
     GPR_ASSERT(GRPC_CALL_OK == error);
 
     pending_client_calls++;
@@ -231,7 +231,7 @@ void resource_quota_server(grpc_end2end_test_config config) {
              pending_server_end_calls >
          0) {
     grpc_event ev =
-        grpc_completion_queue_next(f.cq, n_seconds_from_now(60), NULL);
+        grpc_completion_queue_next(f.cq, n_seconds_from_now(60), nullptr);
     GPR_ASSERT(ev.type == GRPC_OP_COMPLETE);
 
     int ev_tag = (int)(intptr_t)ev.tag;
@@ -278,16 +278,16 @@ void resource_quota_server(grpc_end2end_test_config config) {
       op->op = GRPC_OP_SEND_INITIAL_METADATA;
       op->data.send_initial_metadata.count = 0;
       op->flags = 0;
-      op->reserved = NULL;
+      op->reserved = nullptr;
       op++;
       op->op = GRPC_OP_RECV_MESSAGE;
       op->data.recv_message.recv_message = &request_payload_recv[call_id];
       op->flags = 0;
-      op->reserved = NULL;
+      op->reserved = nullptr;
       op++;
       error =
           grpc_call_start_batch(server_calls[call_id], ops, (size_t)(op - ops),
-                                tag(SERVER_RECV_BASE_TAG + call_id), NULL);
+                                tag(SERVER_RECV_BASE_TAG + call_id), nullptr);
       GPR_ASSERT(GRPC_CALL_OK == error);
 
       GPR_ASSERT(pending_server_start_calls > 0);
@@ -303,12 +303,12 @@ void resource_quota_server(grpc_end2end_test_config config) {
       GPR_ASSERT(call_id < NUM_CALLS);
 
       if (ev.success) {
-        if (request_payload_recv[call_id] != NULL) {
+        if (request_payload_recv[call_id] != nullptr) {
           grpc_byte_buffer_destroy(request_payload_recv[call_id]);
-          request_payload_recv[call_id] = NULL;
+          request_payload_recv[call_id] = nullptr;
         }
       } else {
-        GPR_ASSERT(request_payload_recv[call_id] == NULL);
+        GPR_ASSERT(request_payload_recv[call_id] == nullptr);
       }
 
       memset(ops, 0, sizeof(ops));
@@ -316,7 +316,7 @@ void resource_quota_server(grpc_end2end_test_config config) {
       op->op = GRPC_OP_RECV_CLOSE_ON_SERVER;
       op->data.recv_close_on_server.cancelled = &was_cancelled[call_id];
       op->flags = 0;
-      op->reserved = NULL;
+      op->reserved = nullptr;
       op++;
       op->op = GRPC_OP_SEND_STATUS_FROM_SERVER;
       op->data.send_status_from_server.trailing_metadata_count = 0;
@@ -324,11 +324,11 @@ void resource_quota_server(grpc_end2end_test_config config) {
       grpc_slice status_details = grpc_slice_from_static_string("xyz");
       op->data.send_status_from_server.status_details = &status_details;
       op->flags = 0;
-      op->reserved = NULL;
+      op->reserved = nullptr;
       op++;
       error =
           grpc_call_start_batch(server_calls[call_id], ops, (size_t)(op - ops),
-                                tag(SERVER_END_BASE_TAG + call_id), NULL);
+                                tag(SERVER_END_BASE_TAG + call_id), nullptr);
       GPR_ASSERT(GRPC_CALL_OK == error);
 
       GPR_ASSERT(pending_server_recv_calls > 0);
diff --git a/test/core/end2end/tests/server_finishes_request.cc b/test/core/end2end/tests/server_finishes_request.cc
index 50544a6759..46b874b569 100644
--- a/test/core/end2end/tests/server_finishes_request.cc
+++ b/test/core/end2end/tests/server_finishes_request.cc
@@ -55,7 +55,7 @@ static gpr_timespec five_seconds_from_now(void) {
 static void drain_cq(grpc_completion_queue* cq) {
   grpc_event ev;
   do {
-    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), NULL);
+    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), nullptr);
   } while (ev.type != GRPC_QUEUE_SHUTDOWN);
 }
 
@@ -64,16 +64,16 @@ static void shutdown_server(grpc_end2end_test_fixture* f) {
   grpc_server_shutdown_and_notify(f->server, f->shutdown_cq, tag(1000));
   GPR_ASSERT(grpc_completion_queue_pluck(f->shutdown_cq, tag(1000),
                                          grpc_timeout_seconds_to_deadline(5),
-                                         NULL)
+                                         nullptr)
                  .type == GRPC_OP_COMPLETE);
   grpc_server_destroy(f->server);
-  f->server = NULL;
+  f->server = nullptr;
 }
 
 static void shutdown_client(grpc_end2end_test_fixture* f) {
   if (!f->client) return;
   grpc_channel_destroy(f->client);
-  f->client = NULL;
+  f->client = nullptr;
 }
 
 static void end_test(grpc_end2end_test_fixture* f) {
@@ -104,10 +104,10 @@ static void simple_request_body(grpc_end2end_test_config config,
 
   gpr_timespec deadline = five_seconds_from_now();
   c = grpc_channel_create_call(
-      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+      f.client, nullptr, GRPC_PROPAGATE_DEFAULTS, f.cq,
       grpc_slice_from_static_string("/foo"),
       get_host_override_slice("foo.test.google.fr:1234", config), deadline,
-      NULL);
+      nullptr);
   GPR_ASSERT(c);
 
   grpc_metadata_array_init(&initial_metadata_recv);
@@ -120,21 +120,21 @@ static void simple_request_body(grpc_end2end_test_config config,
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
   op->data.send_initial_metadata.count = 0;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_INITIAL_METADATA;
   op->data.recv_initial_metadata.recv_initial_metadata = &initial_metadata_recv;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_STATUS_ON_CLIENT;
   op->data.recv_status_on_client.trailing_metadata = &trailing_metadata_recv;
   op->data.recv_status_on_client.status = &status;
   op->data.recv_status_on_client.status_details = &details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), NULL);
+  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   error =
@@ -149,7 +149,7 @@ static void simple_request_body(grpc_end2end_test_config config,
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
   op->data.send_initial_metadata.count = 0;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_STATUS_FROM_SERVER;
   op->data.send_status_from_server.trailing_metadata_count = 0;
@@ -157,14 +157,14 @@ static void simple_request_body(grpc_end2end_test_config config,
   grpc_slice status_details = grpc_slice_from_static_string("xyz");
   op->data.send_status_from_server.status_details = &status_details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_CLOSE_ON_SERVER;
   op->data.recv_close_on_server.cancelled = &was_cancelled;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(102), NULL);
+  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(102), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   CQ_EXPECT_COMPLETION(cqv, tag(102), 1);
@@ -193,7 +193,7 @@ static void simple_request_body(grpc_end2end_test_config config,
 static void test_invoke_simple_request(grpc_end2end_test_config config) {
   grpc_end2end_test_fixture f;
 
-  f = begin_test(config, "test_invoke_simple_request", NULL, NULL);
+  f = begin_test(config, "test_invoke_simple_request", nullptr, nullptr);
   simple_request_body(config, f);
   end_test(&f);
   config.tear_down_data(&f);
diff --git a/test/core/end2end/tests/shutdown_finishes_calls.cc b/test/core/end2end/tests/shutdown_finishes_calls.cc
index 26a53e5161..b939877cf0 100644
--- a/test/core/end2end/tests/shutdown_finishes_calls.cc
+++ b/test/core/end2end/tests/shutdown_finishes_calls.cc
@@ -53,14 +53,14 @@ static gpr_timespec five_seconds_from_now(void) {
 static void drain_cq(grpc_completion_queue* cq) {
   grpc_event ev;
   do {
-    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), NULL);
+    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), nullptr);
   } while (ev.type != GRPC_QUEUE_SHUTDOWN);
 }
 
 static void shutdown_client(grpc_end2end_test_fixture* f) {
   if (!f->client) return;
   grpc_channel_destroy(f->client);
-  f->client = NULL;
+  f->client = nullptr;
 }
 
 static void end_test(grpc_end2end_test_fixture* f) {
@@ -78,7 +78,7 @@ static void test_early_server_shutdown_finishes_inflight_calls(
   grpc_call* c;
   grpc_call* s;
   grpc_end2end_test_fixture f = begin_test(
-      config, "test_early_server_shutdown_finishes_inflight_calls", NULL, NULL);
+      config, "test_early_server_shutdown_finishes_inflight_calls", nullptr, nullptr);
   cq_verifier* cqv = cq_verifier_create(f.cq);
   grpc_op ops[6];
   grpc_op* op;
@@ -93,10 +93,10 @@ static void test_early_server_shutdown_finishes_inflight_calls(
 
   gpr_timespec deadline = five_seconds_from_now();
   c = grpc_channel_create_call(
-      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+      f.client, nullptr, GRPC_PROPAGATE_DEFAULTS, f.cq,
       grpc_slice_from_static_string("/foo"),
       get_host_override_slice("foo.test.google.fr:1234", config), deadline,
-      NULL);
+      nullptr);
   GPR_ASSERT(c);
 
   grpc_metadata_array_init(&initial_metadata_recv);
@@ -108,27 +108,27 @@ static void test_early_server_shutdown_finishes_inflight_calls(
   op = ops;
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
   op->data.send_initial_metadata.count = 0;
-  op->data.send_initial_metadata.metadata = NULL;
+  op->data.send_initial_metadata.metadata = nullptr;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_CLOSE_FROM_CLIENT;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_INITIAL_METADATA;
   op->data.recv_initial_metadata.recv_initial_metadata = &initial_metadata_recv;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_STATUS_ON_CLIENT;
   op->data.recv_status_on_client.trailing_metadata = &trailing_metadata_recv;
   op->data.recv_status_on_client.status = &status;
   op->data.recv_status_on_client.status_details = &details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), NULL);
+  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   error =
@@ -143,9 +143,9 @@ static void test_early_server_shutdown_finishes_inflight_calls(
   op->op = GRPC_OP_RECV_CLOSE_ON_SERVER;
   op->data.recv_close_on_server.cancelled = &was_cancelled;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(102), NULL);
+  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(102), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   /* shutdown and destroy the server */
diff --git a/test/core/end2end/tests/shutdown_finishes_tags.cc b/test/core/end2end/tests/shutdown_finishes_tags.cc
index 0275a1e4ef..de64eba612 100644
--- a/test/core/end2end/tests/shutdown_finishes_tags.cc
+++ b/test/core/end2end/tests/shutdown_finishes_tags.cc
@@ -53,14 +53,14 @@ static gpr_timespec five_seconds_from_now(void) {
 static void drain_cq(grpc_completion_queue* cq) {
   grpc_event ev;
   do {
-    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), NULL);
+    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), nullptr);
   } while (ev.type != GRPC_QUEUE_SHUTDOWN);
 }
 
 static void shutdown_client(grpc_end2end_test_fixture* f) {
   if (!f->client) return;
   grpc_channel_destroy(f->client);
-  f->client = NULL;
+  f->client = nullptr;
 }
 
 static void end_test(grpc_end2end_test_fixture* f) {
@@ -76,7 +76,7 @@ static void end_test(grpc_end2end_test_fixture* f) {
 static void test_early_server_shutdown_finishes_tags(
     grpc_end2end_test_config config) {
   grpc_end2end_test_fixture f = begin_test(
-      config, "test_early_server_shutdown_finishes_tags", NULL, NULL);
+      config, "test_early_server_shutdown_finishes_tags", nullptr, nullptr);
   cq_verifier* cqv = cq_verifier_create(f.cq);
   grpc_call* s = (grpc_call*)(uintptr_t)1;
   grpc_call_details call_details;
@@ -94,7 +94,7 @@ static void test_early_server_shutdown_finishes_tags(
   CQ_EXPECT_COMPLETION(cqv, tag(101), 0);
   CQ_EXPECT_COMPLETION(cqv, tag(1000), 1);
   cq_verify(cqv);
-  GPR_ASSERT(s == NULL);
+  GPR_ASSERT(s == nullptr);
 
   grpc_server_destroy(f.server);
 
diff --git a/test/core/end2end/tests/simple_cacheable_request.cc b/test/core/end2end/tests/simple_cacheable_request.cc
index e2ee7bf35a..02c9f49d52 100644
--- a/test/core/end2end/tests/simple_cacheable_request.cc
+++ b/test/core/end2end/tests/simple_cacheable_request.cc
@@ -55,7 +55,7 @@ static gpr_timespec five_seconds_from_now(void) {
 static void drain_cq(grpc_completion_queue* cq) {
   grpc_event ev;
   do {
-    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), NULL);
+    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), nullptr);
   } while (ev.type != GRPC_QUEUE_SHUTDOWN);
 }
 
@@ -64,16 +64,16 @@ static void shutdown_server(grpc_end2end_test_fixture* f) {
   grpc_server_shutdown_and_notify(f->server, f->shutdown_cq, tag(1000));
   GPR_ASSERT(grpc_completion_queue_pluck(f->shutdown_cq, tag(1000),
                                          grpc_timeout_seconds_to_deadline(5),
-                                         NULL)
+                                         nullptr)
                  .type == GRPC_OP_COMPLETE);
   grpc_server_destroy(f->server);
-  f->server = NULL;
+  f->server = nullptr;
 }
 
 static void shutdown_client(grpc_end2end_test_fixture* f) {
   if (!f->client) return;
   grpc_channel_destroy(f->client);
-  f->client = NULL;
+  f->client = nullptr;
 }
 
 static void end_test(grpc_end2end_test_fixture* f) {
@@ -102,30 +102,30 @@ static void test_cacheable_request_response_with_metadata_and_payload(
   grpc_metadata meta_c[2] = {{grpc_slice_from_static_string("key1"),
                               grpc_slice_from_static_string("val1"),
                               0,
-                              {{NULL, NULL, NULL, NULL}}},
+                              {{nullptr, nullptr, nullptr, nullptr}}},
                              {grpc_slice_from_static_string("key2"),
                               grpc_slice_from_static_string("val2"),
                               0,
-                              {{NULL, NULL, NULL, NULL}}}};
+                              {{nullptr, nullptr, nullptr, nullptr}}}};
   grpc_metadata meta_s[2] = {{grpc_slice_from_static_string("key3"),
                               grpc_slice_from_static_string("val3"),
                               0,
-                              {{NULL, NULL, NULL, NULL}}},
+                              {{nullptr, nullptr, nullptr, nullptr}}},
                              {grpc_slice_from_static_string("key4"),
                               grpc_slice_from_static_string("val4"),
                               0,
-                              {{NULL, NULL, NULL, NULL}}}};
+                              {{nullptr, nullptr, nullptr, nullptr}}}};
   grpc_end2end_test_fixture f = begin_test(
-      config, "test_cacheable_request_response_with_metadata_and_payload", NULL,
-      NULL);
+      config, "test_cacheable_request_response_with_metadata_and_payload", nullptr,
+      nullptr);
   cq_verifier* cqv = cq_verifier_create(f.cq);
   grpc_op ops[6];
   grpc_op* op;
   grpc_metadata_array initial_metadata_recv;
   grpc_metadata_array trailing_metadata_recv;
   grpc_metadata_array request_metadata_recv;
-  grpc_byte_buffer* request_payload_recv = NULL;
-  grpc_byte_buffer* response_payload_recv = NULL;
+  grpc_byte_buffer* request_payload_recv = nullptr;
+  grpc_byte_buffer* response_payload_recv = nullptr;
   grpc_call_details call_details;
   grpc_status_code status;
   grpc_call_error error;
@@ -134,10 +134,10 @@ static void test_cacheable_request_response_with_metadata_and_payload(
 
   gpr_timespec deadline = five_seconds_from_now();
   c = grpc_channel_create_call(
-      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+      f.client, nullptr, GRPC_PROPAGATE_DEFAULTS, f.cq,
       grpc_slice_from_static_string("/foo"),
       get_host_override_slice("foo.test.google.fr:1234", config), deadline,
-      NULL);
+      nullptr);
   GPR_ASSERT(c);
 
   grpc_metadata_array_init(&initial_metadata_recv);
@@ -151,35 +151,35 @@ static void test_cacheable_request_response_with_metadata_and_payload(
   op->data.send_initial_metadata.count = 2;
   op->data.send_initial_metadata.metadata = meta_c;
   op->flags = GRPC_INITIAL_METADATA_CACHEABLE_REQUEST;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_MESSAGE;
   op->data.send_message.send_message = request_payload;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_CLOSE_FROM_CLIENT;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_INITIAL_METADATA;
   op->data.recv_initial_metadata.recv_initial_metadata = &initial_metadata_recv;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_MESSAGE;
   op->data.recv_message.recv_message = &response_payload_recv;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_STATUS_ON_CLIENT;
   op->data.recv_status_on_client.trailing_metadata = &trailing_metadata_recv;
   op->data.recv_status_on_client.status = &status;
   op->data.recv_status_on_client.status_details = &details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), NULL);
+  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   error =
@@ -195,14 +195,14 @@ static void test_cacheable_request_response_with_metadata_and_payload(
   op->data.send_initial_metadata.count = 2;
   op->data.send_initial_metadata.metadata = meta_s;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_MESSAGE;
   op->data.recv_message.recv_message = &request_payload_recv;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(102), NULL);
+  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(102), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   CQ_EXPECT_COMPLETION(cqv, tag(102), 1);
@@ -213,12 +213,12 @@ static void test_cacheable_request_response_with_metadata_and_payload(
   op->op = GRPC_OP_RECV_CLOSE_ON_SERVER;
   op->data.recv_close_on_server.cancelled = &was_cancelled;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_MESSAGE;
   op->data.send_message.send_message = response_payload;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_STATUS_FROM_SERVER;
   op->data.send_status_from_server.trailing_metadata_count = 0;
@@ -226,9 +226,9 @@ static void test_cacheable_request_response_with_metadata_and_payload(
   grpc_slice status_details = grpc_slice_from_static_string("xyz");
   op->data.send_status_from_server.status_details = &status_details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(103), NULL);
+  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(103), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   CQ_EXPECT_COMPLETION(cqv, tag(103), 1);
diff --git a/test/core/end2end/tests/simple_delayed_request.cc b/test/core/end2end/tests/simple_delayed_request.cc
index eef36c9710..0ad224f579 100644
--- a/test/core/end2end/tests/simple_delayed_request.cc
+++ b/test/core/end2end/tests/simple_delayed_request.cc
@@ -41,7 +41,7 @@ static gpr_timespec five_seconds_from_now(void) {
 static void drain_cq(grpc_completion_queue* cq) {
   grpc_event ev;
   do {
-    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), NULL);
+    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), nullptr);
   } while (ev.type != GRPC_QUEUE_SHUTDOWN);
 }
 
@@ -50,16 +50,16 @@ static void shutdown_server(grpc_end2end_test_fixture* f) {
   grpc_server_shutdown_and_notify(f->server, f->shutdown_cq, tag(1000));
   GPR_ASSERT(grpc_completion_queue_pluck(f->shutdown_cq, tag(1000),
                                          grpc_timeout_seconds_to_deadline(5),
-                                         NULL)
+                                         nullptr)
                  .type == GRPC_OP_COMPLETE);
   grpc_server_destroy(f->server);
-  f->server = NULL;
+  f->server = nullptr;
 }
 
 static void shutdown_client(grpc_end2end_test_fixture* f) {
   if (!f->client) return;
   grpc_channel_destroy(f->client);
-  f->client = NULL;
+  f->client = nullptr;
 }
 
 static void end_test(grpc_end2end_test_fixture* f) {
@@ -96,10 +96,10 @@ static void simple_delayed_request_body(grpc_end2end_test_config config,
 
   gpr_timespec deadline = five_seconds_from_now();
   c = grpc_channel_create_call(
-      f->client, NULL, GRPC_PROPAGATE_DEFAULTS, f->cq,
+      f->client, nullptr, GRPC_PROPAGATE_DEFAULTS, f->cq,
       grpc_slice_from_static_string("/foo"),
       get_host_override_slice("foo.test.google.fr:1234", config), deadline,
-      NULL);
+      nullptr);
   GPR_ASSERT(c);
 
   grpc_metadata_array_init(&initial_metadata_recv);
@@ -112,25 +112,25 @@ static void simple_delayed_request_body(grpc_end2end_test_config config,
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
   op->data.send_initial_metadata.count = 0;
   op->flags = GRPC_INITIAL_METADATA_WAIT_FOR_READY;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_CLOSE_FROM_CLIENT;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_INITIAL_METADATA;
   op->data.recv_initial_metadata.recv_initial_metadata = &initial_metadata_recv;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_STATUS_ON_CLIENT;
   op->data.recv_status_on_client.trailing_metadata = &trailing_metadata_recv;
   op->data.recv_status_on_client.status = &status;
   op->data.recv_status_on_client.status_details = &details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), NULL);
+  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   error =
@@ -145,7 +145,7 @@ static void simple_delayed_request_body(grpc_end2end_test_config config,
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
   op->data.send_initial_metadata.count = 0;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_STATUS_FROM_SERVER;
   op->data.send_status_from_server.trailing_metadata_count = 0;
@@ -153,14 +153,14 @@ static void simple_delayed_request_body(grpc_end2end_test_config config,
   grpc_slice status_details = grpc_slice_from_static_string("xyz");
   op->data.send_status_from_server.status_details = &status_details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_CLOSE_ON_SERVER;
   op->data.recv_close_on_server.cancelled = &was_cancelled;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(102), NULL);
+  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(102), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   CQ_EXPECT_COMPLETION(cqv, tag(102), 1);
@@ -199,9 +199,9 @@ static void test_simple_delayed_request_short(grpc_end2end_test_config config) {
 
   gpr_log(GPR_INFO, "Running test: %s/%s", "test_simple_delayed_request_short",
           config.name);
-  f = config.create_fixture(NULL, NULL);
+  f = config.create_fixture(nullptr, nullptr);
 
-  simple_delayed_request_body(config, &f, &client_args, NULL, 100000);
+  simple_delayed_request_body(config, &f, &client_args, nullptr, 100000);
   end_test(&f);
   config.tear_down_data(&f);
 }
@@ -219,9 +219,9 @@ static void test_simple_delayed_request_long(grpc_end2end_test_config config) {
 
   gpr_log(GPR_INFO, "Running test: %s/%s", "test_simple_delayed_request_long",
           config.name);
-  f = config.create_fixture(NULL, NULL);
+  f = config.create_fixture(nullptr, nullptr);
   /* This timeout should be longer than a single retry */
-  simple_delayed_request_body(config, &f, &client_args, NULL, 1500000);
+  simple_delayed_request_body(config, &f, &client_args, nullptr, 1500000);
   end_test(&f);
   config.tear_down_data(&f);
 }
diff --git a/test/core/end2end/tests/simple_metadata.cc b/test/core/end2end/tests/simple_metadata.cc
index 3b3d5ad64c..38adcbae28 100644
--- a/test/core/end2end/tests/simple_metadata.cc
+++ b/test/core/end2end/tests/simple_metadata.cc
@@ -53,7 +53,7 @@ static gpr_timespec five_seconds_from_now(void) {
 static void drain_cq(grpc_completion_queue* cq) {
   grpc_event ev;
   do {
-    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), NULL);
+    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), nullptr);
   } while (ev.type != GRPC_QUEUE_SHUTDOWN);
 }
 
@@ -62,16 +62,16 @@ static void shutdown_server(grpc_end2end_test_fixture* f) {
   grpc_server_shutdown_and_notify(f->server, f->shutdown_cq, tag(1000));
   GPR_ASSERT(grpc_completion_queue_pluck(f->shutdown_cq, tag(1000),
                                          grpc_timeout_seconds_to_deadline(5),
-                                         NULL)
+                                         nullptr)
                  .type == GRPC_OP_COMPLETE);
   grpc_server_destroy(f->server);
-  f->server = NULL;
+  f->server = nullptr;
 }
 
 static void shutdown_client(grpc_end2end_test_fixture* f) {
   if (!f->client) return;
   grpc_channel_destroy(f->client);
-  f->client = NULL;
+  f->client = nullptr;
 }
 
 static void end_test(grpc_end2end_test_fixture* f) {
@@ -100,29 +100,29 @@ static void test_request_response_with_metadata_and_payload(
   grpc_metadata meta_c[2] = {{grpc_slice_from_static_string("key1"),
                               grpc_slice_from_static_string("val1"),
                               0,
-                              {{NULL, NULL, NULL, NULL}}},
+                              {{nullptr, nullptr, nullptr, nullptr}}},
                              {grpc_slice_from_static_string("key2"),
                               grpc_slice_from_static_string("val2"),
                               0,
-                              {{NULL, NULL, NULL, NULL}}}};
+                              {{nullptr, nullptr, nullptr, nullptr}}}};
   grpc_metadata meta_s[2] = {{grpc_slice_from_static_string("key3"),
                               grpc_slice_from_static_string("val3"),
                               0,
-                              {{NULL, NULL, NULL, NULL}}},
+                              {{nullptr, nullptr, nullptr, nullptr}}},
                              {grpc_slice_from_static_string("key4"),
                               grpc_slice_from_static_string("val4"),
                               0,
-                              {{NULL, NULL, NULL, NULL}}}};
+                              {{nullptr, nullptr, nullptr, nullptr}}}};
   grpc_end2end_test_fixture f = begin_test(
-      config, "test_request_response_with_metadata_and_payload", NULL, NULL);
+      config, "test_request_response_with_metadata_and_payload", nullptr, nullptr);
   cq_verifier* cqv = cq_verifier_create(f.cq);
   grpc_op ops[6];
   grpc_op* op;
   grpc_metadata_array initial_metadata_recv;
   grpc_metadata_array trailing_metadata_recv;
   grpc_metadata_array request_metadata_recv;
-  grpc_byte_buffer* request_payload_recv = NULL;
-  grpc_byte_buffer* response_payload_recv = NULL;
+  grpc_byte_buffer* request_payload_recv = nullptr;
+  grpc_byte_buffer* response_payload_recv = nullptr;
   grpc_call_details call_details;
   grpc_status_code status;
   grpc_call_error error;
@@ -131,10 +131,10 @@ static void test_request_response_with_metadata_and_payload(
 
   gpr_timespec deadline = five_seconds_from_now();
   c = grpc_channel_create_call(
-      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+      f.client, nullptr, GRPC_PROPAGATE_DEFAULTS, f.cq,
       grpc_slice_from_static_string("/foo"),
       get_host_override_slice("foo.test.google.fr:1234", config), deadline,
-      NULL);
+      nullptr);
   GPR_ASSERT(c);
 
   grpc_metadata_array_init(&initial_metadata_recv);
@@ -148,35 +148,35 @@ static void test_request_response_with_metadata_and_payload(
   op->data.send_initial_metadata.count = 2;
   op->data.send_initial_metadata.metadata = meta_c;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_MESSAGE;
   op->data.send_message.send_message = request_payload;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_CLOSE_FROM_CLIENT;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_INITIAL_METADATA;
   op->data.recv_initial_metadata.recv_initial_metadata = &initial_metadata_recv;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_MESSAGE;
   op->data.recv_message.recv_message = &response_payload_recv;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_STATUS_ON_CLIENT;
   op->data.recv_status_on_client.trailing_metadata = &trailing_metadata_recv;
   op->data.recv_status_on_client.status = &status;
   op->data.recv_status_on_client.status_details = &details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), NULL);
+  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   error =
@@ -192,14 +192,14 @@ static void test_request_response_with_metadata_and_payload(
   op->data.send_initial_metadata.count = 2;
   op->data.send_initial_metadata.metadata = meta_s;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_MESSAGE;
   op->data.recv_message.recv_message = &request_payload_recv;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(102), NULL);
+  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(102), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   CQ_EXPECT_COMPLETION(cqv, tag(102), 1);
@@ -210,12 +210,12 @@ static void test_request_response_with_metadata_and_payload(
   op->op = GRPC_OP_RECV_CLOSE_ON_SERVER;
   op->data.recv_close_on_server.cancelled = &was_cancelled;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_MESSAGE;
   op->data.send_message.send_message = response_payload;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_STATUS_FROM_SERVER;
   op->data.send_status_from_server.trailing_metadata_count = 0;
@@ -223,9 +223,9 @@ static void test_request_response_with_metadata_and_payload(
   grpc_slice status_details = grpc_slice_from_static_string("xyz");
   op->data.send_status_from_server.status_details = &status_details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(103), NULL);
+  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(103), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   CQ_EXPECT_COMPLETION(cqv, tag(103), 1);
diff --git a/test/core/end2end/tests/simple_request.cc b/test/core/end2end/tests/simple_request.cc
index d48010ba87..ec7425aa09 100644
--- a/test/core/end2end/tests/simple_request.cc
+++ b/test/core/end2end/tests/simple_request.cc
@@ -56,7 +56,7 @@ static gpr_timespec five_seconds_from_now(void) {
 static void drain_cq(grpc_completion_queue* cq) {
   grpc_event ev;
   do {
-    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), NULL);
+    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), nullptr);
   } while (ev.type != GRPC_QUEUE_SHUTDOWN);
 }
 
@@ -65,16 +65,16 @@ static void shutdown_server(grpc_end2end_test_fixture* f) {
   grpc_server_shutdown_and_notify(f->server, f->shutdown_cq, tag(1000));
   GPR_ASSERT(grpc_completion_queue_pluck(f->shutdown_cq, tag(1000),
                                          grpc_timeout_seconds_to_deadline(5),
-                                         NULL)
+                                         nullptr)
                  .type == GRPC_OP_COMPLETE);
   grpc_server_destroy(f->server);
-  f->server = NULL;
+  f->server = nullptr;
 }
 
 static void shutdown_client(grpc_end2end_test_fixture* f) {
   if (!f->client) return;
   grpc_channel_destroy(f->client);
-  f->client = NULL;
+  f->client = nullptr;
 }
 
 static void end_test(grpc_end2end_test_fixture* f) {
@@ -112,14 +112,14 @@ static void simple_request_body(grpc_end2end_test_config config,
 
   gpr_timespec deadline = five_seconds_from_now();
   c = grpc_channel_create_call(
-      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+      f.client, nullptr, GRPC_PROPAGATE_DEFAULTS, f.cq,
       grpc_slice_from_static_string("/foo"),
       get_host_override_slice("foo.test.google.fr:1234", config), deadline,
-      NULL);
+      nullptr);
   GPR_ASSERT(c);
 
   peer = grpc_call_get_peer(c);
-  GPR_ASSERT(peer != NULL);
+  GPR_ASSERT(peer != nullptr);
   gpr_log(GPR_DEBUG, "client_peer_before_call=%s", peer);
   gpr_free(peer);
 
@@ -133,25 +133,25 @@ static void simple_request_body(grpc_end2end_test_config config,
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
   op->data.send_initial_metadata.count = 0;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_CLOSE_FROM_CLIENT;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_INITIAL_METADATA;
   op->data.recv_initial_metadata.recv_initial_metadata = &initial_metadata_recv;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_STATUS_ON_CLIENT;
   op->data.recv_status_on_client.trailing_metadata = &trailing_metadata_recv;
   op->data.recv_status_on_client.status = &status;
   op->data.recv_status_on_client.status_details = &details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), NULL);
+  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   error =
@@ -162,11 +162,11 @@ static void simple_request_body(grpc_end2end_test_config config,
   cq_verify(cqv);
 
   peer = grpc_call_get_peer(s);
-  GPR_ASSERT(peer != NULL);
+  GPR_ASSERT(peer != nullptr);
   gpr_log(GPR_DEBUG, "server_peer=%s", peer);
   gpr_free(peer);
   peer = grpc_call_get_peer(c);
-  GPR_ASSERT(peer != NULL);
+  GPR_ASSERT(peer != nullptr);
   gpr_log(GPR_DEBUG, "client_peer=%s", peer);
   gpr_free(peer);
 
@@ -175,7 +175,7 @@ static void simple_request_body(grpc_end2end_test_config config,
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
   op->data.send_initial_metadata.count = 0;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_STATUS_FROM_SERVER;
   op->data.send_status_from_server.trailing_metadata_count = 0;
@@ -183,14 +183,14 @@ static void simple_request_body(grpc_end2end_test_config config,
   grpc_slice status_details = grpc_slice_from_static_string("xyz");
   op->data.send_status_from_server.status_details = &status_details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_CLOSE_ON_SERVER;
   op->data.recv_close_on_server.cancelled = &was_cancelled;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(102), NULL);
+  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(102), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   CQ_EXPECT_COMPLETION(cqv, tag(102), 1);
@@ -239,7 +239,7 @@ static void simple_request_body(grpc_end2end_test_config config,
 static void test_invoke_simple_request(grpc_end2end_test_config config) {
   grpc_end2end_test_fixture f;
 
-  f = begin_test(config, "test_invoke_simple_request", NULL, NULL);
+  f = begin_test(config, "test_invoke_simple_request", nullptr, nullptr);
   simple_request_body(config, f);
   end_test(&f);
   config.tear_down_data(&f);
@@ -248,7 +248,7 @@ static void test_invoke_simple_request(grpc_end2end_test_config config) {
 static void test_invoke_10_simple_requests(grpc_end2end_test_config config) {
   int i;
   grpc_end2end_test_fixture f =
-      begin_test(config, "test_invoke_10_simple_requests", NULL, NULL);
+      begin_test(config, "test_invoke_10_simple_requests", nullptr, nullptr);
   for (i = 0; i < 10; i++) {
     simple_request_body(config, f);
     gpr_log(GPR_INFO, "Running test: Passed simple request %d", i);
diff --git a/test/core/end2end/tests/stream_compression_compressed_payload.cc b/test/core/end2end/tests/stream_compression_compressed_payload.cc
index 3fe5200045..e662a38a30 100644
--- a/test/core/end2end/tests/stream_compression_compressed_payload.cc
+++ b/test/core/end2end/tests/stream_compression_compressed_payload.cc
@@ -61,7 +61,7 @@ static gpr_timespec five_seconds_from_now(void) {
 static void drain_cq(grpc_completion_queue* cq) {
   grpc_event ev;
   do {
-    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), NULL);
+    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), nullptr);
   } while (ev.type != GRPC_QUEUE_SHUTDOWN);
 }
 
@@ -70,16 +70,16 @@ static void shutdown_server(grpc_end2end_test_fixture* f) {
   grpc_server_shutdown_and_notify(f->server, f->shutdown_cq, tag(1000));
   GPR_ASSERT(grpc_completion_queue_pluck(f->shutdown_cq, tag(1000),
                                          grpc_timeout_seconds_to_deadline(5),
-                                         NULL)
+                                         nullptr)
                  .type == GRPC_OP_COMPLETE);
   grpc_server_destroy(f->server);
-  f->server = NULL;
+  f->server = nullptr;
 }
 
 static void shutdown_client(grpc_end2end_test_fixture* f) {
   if (!f->client) return;
   grpc_channel_destroy(f->client);
-  f->client = NULL;
+  f->client = nullptr;
 }
 
 static void end_test(grpc_end2end_test_fixture* f) {
@@ -110,7 +110,7 @@ static void request_for_disabled_algorithm(
   grpc_metadata_array initial_metadata_recv;
   grpc_metadata_array trailing_metadata_recv;
   grpc_metadata_array request_metadata_recv;
-  grpc_byte_buffer* request_payload_recv = NULL;
+  grpc_byte_buffer* request_payload_recv = nullptr;
   grpc_call_details call_details;
   grpc_status_code status;
   grpc_call_error error;
@@ -125,9 +125,9 @@ static void request_for_disabled_algorithm(
   request_payload = grpc_raw_byte_buffer_create(&request_payload_slice, 1);
 
   client_args = grpc_channel_args_set_stream_compression_algorithm(
-      NULL, requested_client_compression_algorithm);
+      nullptr, requested_client_compression_algorithm);
   server_args = grpc_channel_args_set_stream_compression_algorithm(
-      NULL, GRPC_STREAM_COMPRESS_NONE);
+      nullptr, GRPC_STREAM_COMPRESS_NONE);
   {
     grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
     server_args = grpc_channel_args_stream_compression_algorithm_set_state(
@@ -140,10 +140,10 @@ static void request_for_disabled_algorithm(
 
   gpr_timespec deadline = five_seconds_from_now();
   c = grpc_channel_create_call(
-      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+      f.client, nullptr, GRPC_PROPAGATE_DEFAULTS, f.cq,
       grpc_slice_from_static_string("/foo"),
       get_host_override_slice("foo.test.google.fr:1234", config), deadline,
-      NULL);
+      nullptr);
   GPR_ASSERT(c);
 
   grpc_metadata_array_init(&initial_metadata_recv);
@@ -159,37 +159,37 @@ static void request_for_disabled_algorithm(
   memset(ops, 0, sizeof(ops));
   op = ops;
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
-  if (client_metadata != NULL) {
+  if (client_metadata != nullptr) {
     op->data.send_initial_metadata.count = 1;
     op->data.send_initial_metadata.metadata = client_metadata;
   } else {
     op->data.send_initial_metadata.count = 0;
   }
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_MESSAGE;
   op->data.send_message.send_message = request_payload;
   op->flags = send_flags_bitmask;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_CLOSE_FROM_CLIENT;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_INITIAL_METADATA;
   op->data.recv_initial_metadata.recv_initial_metadata = &initial_metadata_recv;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_STATUS_ON_CLIENT;
   op->data.recv_status_on_client.trailing_metadata = &trailing_metadata_recv;
   op->data.recv_status_on_client.status = &status;
   op->data.recv_status_on_client.status_details = &details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), NULL);
+  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   CQ_EXPECT_COMPLETION(cqv, tag(101), true);
@@ -200,14 +200,14 @@ static void request_for_disabled_algorithm(
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
   op->data.send_initial_metadata.count = 0;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_MESSAGE;
   op->data.recv_message.recv_message = &request_payload_recv;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(102), NULL);
+  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(102), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   CQ_EXPECT_COMPLETION(cqv, tag(102), false);
@@ -216,9 +216,9 @@ static void request_for_disabled_algorithm(
   op->op = GRPC_OP_RECV_CLOSE_ON_SERVER;
   op->data.recv_close_on_server.cancelled = &was_cancelled;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(103), NULL);
+  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(103), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   CQ_EXPECT_COMPLETION(cqv, tag(103), true);
@@ -229,10 +229,10 @@ static void request_for_disabled_algorithm(
   /* with a certain error */
   GPR_ASSERT(status == expected_error);
 
-  const char* algo_name = NULL;
+  const char* algo_name = nullptr;
   GPR_ASSERT(
       grpc_stream_compression_algorithm_name(algorithm_to_disable, &algo_name));
-  char* expected_details = NULL;
+  char* expected_details = nullptr;
   gpr_asprintf(&expected_details,
                "Stream compression algorithm '%s' is disabled.", algo_name);
   /* and we expect a specific reason for it */
@@ -285,7 +285,7 @@ static void request_with_payload_template(
   grpc_call* c;
   grpc_call* s;
   grpc_slice request_payload_slice;
-  grpc_byte_buffer* request_payload = NULL;
+  grpc_byte_buffer* request_payload = nullptr;
   grpc_channel_args* client_args;
   grpc_channel_args* server_args;
   grpc_end2end_test_fixture f;
@@ -294,7 +294,7 @@ static void request_with_payload_template(
   grpc_metadata_array initial_metadata_recv;
   grpc_metadata_array trailing_metadata_recv;
   grpc_metadata_array request_metadata_recv;
-  grpc_byte_buffer* request_payload_recv = NULL;
+  grpc_byte_buffer* request_payload_recv = nullptr;
   grpc_byte_buffer* response_payload;
   grpc_byte_buffer* response_payload_recv;
   grpc_call_details call_details;
@@ -317,13 +317,13 @@ static void request_with_payload_template(
       grpc_slice_from_copied_string(response_str);
 
   client_args = grpc_channel_args_set_stream_compression_algorithm(
-      NULL, default_client_channel_compression_algorithm);
+      nullptr, default_client_channel_compression_algorithm);
   if (set_default_server_message_compression_algorithm) {
     server_args = grpc_channel_args_set_compression_algorithm(
-        NULL, default_server_message_compression_algorithm);
+        nullptr, default_server_message_compression_algorithm);
   } else {
     server_args = grpc_channel_args_set_stream_compression_algorithm(
-        NULL, default_server_channel_compression_algorithm);
+        nullptr, default_server_channel_compression_algorithm);
   }
 
   f = begin_test(config, test_name, client_args, server_args);
@@ -331,10 +331,10 @@ static void request_with_payload_template(
 
   gpr_timespec deadline = five_seconds_from_now();
   c = grpc_channel_create_call(
-      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+      f.client, nullptr, GRPC_PROPAGATE_DEFAULTS, f.cq,
       grpc_slice_from_static_string("/foo"),
       get_host_override_slice("foo.test.google.fr:1234", config), deadline,
-      NULL);
+      nullptr);
   GPR_ASSERT(c);
 
   grpc_metadata_array_init(&initial_metadata_recv);
@@ -349,9 +349,9 @@ static void request_with_payload_template(
     op->op = GRPC_OP_SEND_MESSAGE;
     op->data.send_message.send_message = request_payload;
     op->flags = client_send_flags_bitmask;
-    op->reserved = NULL;
+    op->reserved = nullptr;
     op++;
-    error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(2), NULL);
+    error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(2), nullptr);
     GPR_ASSERT(GRPC_CALL_OK == error);
     CQ_EXPECT_COMPLETION(cqv, tag(2), true);
   }
@@ -359,28 +359,28 @@ static void request_with_payload_template(
   memset(ops, 0, sizeof(ops));
   op = ops;
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
-  if (client_init_metadata != NULL) {
+  if (client_init_metadata != nullptr) {
     op->data.send_initial_metadata.count = 1;
     op->data.send_initial_metadata.metadata = client_init_metadata;
   } else {
     op->data.send_initial_metadata.count = 0;
   }
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_INITIAL_METADATA;
   op->data.recv_initial_metadata.recv_initial_metadata = &initial_metadata_recv;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_STATUS_ON_CLIENT;
   op->data.recv_status_on_client.trailing_metadata = &trailing_metadata_recv;
   op->data.recv_status_on_client.status = &status;
   op->data.recv_status_on_client.status_details = &details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), NULL);
+  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   error =
@@ -418,14 +418,14 @@ static void request_with_payload_template(
         server_compression_level;
   }
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_CLOSE_ON_SERVER;
   op->data.recv_close_on_server.cancelled = &was_cancelled;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(101), NULL);
+  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(101), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   for (int i = 0; i < 2; i++) {
@@ -438,9 +438,9 @@ static void request_with_payload_template(
       op->op = GRPC_OP_SEND_MESSAGE;
       op->data.send_message.send_message = request_payload;
       op->flags = client_send_flags_bitmask;
-      op->reserved = NULL;
+      op->reserved = nullptr;
       op++;
-      error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(2), NULL);
+      error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(2), nullptr);
       GPR_ASSERT(GRPC_CALL_OK == error);
       CQ_EXPECT_COMPLETION(cqv, tag(2), 1);
     }
@@ -450,9 +450,9 @@ static void request_with_payload_template(
     op->op = GRPC_OP_RECV_MESSAGE;
     op->data.recv_message.recv_message = &request_payload_recv;
     op->flags = 0;
-    op->reserved = NULL;
+    op->reserved = nullptr;
     op++;
-    error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(102), NULL);
+    error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(102), nullptr);
     GPR_ASSERT(GRPC_CALL_OK == error);
 
     CQ_EXPECT_COMPLETION(cqv, tag(102), 1);
@@ -466,9 +466,9 @@ static void request_with_payload_template(
     op->op = GRPC_OP_SEND_MESSAGE;
     op->data.send_message.send_message = response_payload;
     op->flags = 0;
-    op->reserved = NULL;
+    op->reserved = nullptr;
     op++;
-    error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(103), NULL);
+    error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(103), nullptr);
     GPR_ASSERT(GRPC_CALL_OK == error);
 
     memset(ops, 0, sizeof(ops));
@@ -476,9 +476,9 @@ static void request_with_payload_template(
     op->op = GRPC_OP_RECV_MESSAGE;
     op->data.recv_message.recv_message = &response_payload_recv;
     op->flags = 0;
-    op->reserved = NULL;
+    op->reserved = nullptr;
     op++;
-    error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(3), NULL);
+    error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(3), nullptr);
     GPR_ASSERT(GRPC_CALL_OK == error);
 
     CQ_EXPECT_COMPLETION(cqv, tag(103), 1);
@@ -501,9 +501,9 @@ static void request_with_payload_template(
   op = ops;
   op->op = GRPC_OP_SEND_CLOSE_FROM_CLIENT;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(4), NULL);
+  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(4), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   memset(ops, 0, sizeof(ops));
@@ -514,9 +514,9 @@ static void request_with_payload_template(
   grpc_slice status_details = grpc_slice_from_static_string("xyz");
   op->data.send_status_from_server.status_details = &status_details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(104), NULL);
+  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(104), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   CQ_EXPECT_COMPLETION(cqv, tag(1), 1);
@@ -559,7 +559,7 @@ static void test_invoke_request_with_compressed_payload(
   request_with_payload_template(
       config, "test_invoke_request_with_compressed_payload", 0,
       GRPC_STREAM_COMPRESS_GZIP, GRPC_STREAM_COMPRESS_GZIP,
-      GRPC_STREAM_COMPRESS_GZIP, GRPC_STREAM_COMPRESS_GZIP, NULL,
+      GRPC_STREAM_COMPRESS_GZIP, GRPC_STREAM_COMPRESS_GZIP, nullptr,
       false, /* ignored */
       GRPC_STREAM_COMPRESS_LEVEL_NONE, false, false, GRPC_COMPRESS_NONE);
 }
@@ -569,7 +569,7 @@ static void test_invoke_request_with_send_message_before_initial_metadata(
   request_with_payload_template(
       config, "test_invoke_request_with_send_message_before_initial_metadata",
       0, GRPC_STREAM_COMPRESS_GZIP, GRPC_STREAM_COMPRESS_GZIP,
-      GRPC_STREAM_COMPRESS_GZIP, GRPC_STREAM_COMPRESS_GZIP, NULL,
+      GRPC_STREAM_COMPRESS_GZIP, GRPC_STREAM_COMPRESS_GZIP, nullptr,
       false, /* ignored */
       GRPC_STREAM_COMPRESS_LEVEL_NONE, true, false, GRPC_COMPRESS_NONE);
 }
@@ -580,7 +580,7 @@ static void test_invoke_request_with_server_level(
       config, "test_invoke_request_with_server_level", 0,
       GRPC_STREAM_COMPRESS_NONE, GRPC_STREAM_COMPRESS_NONE,
       GRPC_STREAM_COMPRESS_NONE, GRPC_STREAM_COMPRESS_GZIP,
-      /* ignored */ NULL, true, GRPC_STREAM_COMPRESS_LEVEL_HIGH, false, false,
+      /* ignored */ nullptr, true, GRPC_STREAM_COMPRESS_LEVEL_HIGH, false, false,
       GRPC_COMPRESS_NONE);
 }
 
@@ -626,7 +626,7 @@ static void test_invoke_request_with_disabled_algorithm(
   request_for_disabled_algorithm(
       config, "test_invoke_request_with_disabled_algorithm", 0,
       GRPC_STREAM_COMPRESS_GZIP, GRPC_STREAM_COMPRESS_GZIP,
-      GRPC_STATUS_UNIMPLEMENTED, NULL);
+      GRPC_STATUS_UNIMPLEMENTED, nullptr);
 }
 
 static void test_stream_compression_override_message_compression(
@@ -638,7 +638,7 @@ static void test_stream_compression_override_message_compression(
       GRPC_STREAM_COMPRESS_NONE,
       grpc_stream_compression_algorithm_for_level(
           level, (1u << GRPC_STREAM_COMPRESS_ALGORITHMS_COUNT) - 1),
-      /* ignored */ NULL, true, level, false, true, GRPC_COMPRESS_GZIP);
+      /* ignored */ nullptr, true, level, false, true, GRPC_COMPRESS_GZIP);
 }
 
 void stream_compression_compressed_payload(grpc_end2end_test_config config) {
diff --git a/test/core/end2end/tests/stream_compression_payload.cc b/test/core/end2end/tests/stream_compression_payload.cc
index 038f0be738..924961ea55 100644
--- a/test/core/end2end/tests/stream_compression_payload.cc
+++ b/test/core/end2end/tests/stream_compression_payload.cc
@@ -56,7 +56,7 @@ static gpr_timespec five_seconds_from_now(void) {
 static void drain_cq(grpc_completion_queue* cq) {
   grpc_event ev;
   do {
-    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), NULL);
+    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), nullptr);
   } while (ev.type != GRPC_QUEUE_SHUTDOWN);
 }
 
@@ -65,16 +65,16 @@ static void shutdown_server(grpc_end2end_test_fixture* f) {
   grpc_server_shutdown_and_notify(f->server, f->shutdown_cq, tag(1000));
   GPR_ASSERT(grpc_completion_queue_pluck(f->shutdown_cq, tag(1000),
                                          grpc_timeout_seconds_to_deadline(5),
-                                         NULL)
+                                         nullptr)
                  .type == GRPC_OP_COMPLETE);
   grpc_server_destroy(f->server);
-  f->server = NULL;
+  f->server = nullptr;
 }
 
 static void shutdown_client(grpc_end2end_test_fixture* f) {
   if (!f->client) return;
   grpc_channel_destroy(f->client);
-  f->client = NULL;
+  f->client = nullptr;
 }
 
 static void end_test(grpc_end2end_test_fixture* f) {
@@ -124,8 +124,8 @@ static void request_response_with_payload(grpc_end2end_test_config config,
   grpc_metadata_array initial_metadata_recv;
   grpc_metadata_array trailing_metadata_recv;
   grpc_metadata_array request_metadata_recv;
-  grpc_byte_buffer* request_payload_recv = NULL;
-  grpc_byte_buffer* response_payload_recv = NULL;
+  grpc_byte_buffer* request_payload_recv = nullptr;
+  grpc_byte_buffer* response_payload_recv = nullptr;
   grpc_call_details call_details;
   grpc_status_code status;
   grpc_call_error error;
@@ -134,10 +134,10 @@ static void request_response_with_payload(grpc_end2end_test_config config,
 
   gpr_timespec deadline = n_seconds_from_now(60);
   c = grpc_channel_create_call(
-      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+      f.client, nullptr, GRPC_PROPAGATE_DEFAULTS, f.cq,
       grpc_slice_from_static_string("/foo"),
       get_host_override_slice("foo.test.google.fr:1234", config), deadline,
-      NULL);
+      nullptr);
   GPR_ASSERT(c);
 
   grpc_metadata_array_init(&initial_metadata_recv);
@@ -150,35 +150,35 @@ static void request_response_with_payload(grpc_end2end_test_config config,
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
   op->data.send_initial_metadata.count = 0;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_MESSAGE;
   op->data.send_message.send_message = request_payload;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_CLOSE_FROM_CLIENT;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_INITIAL_METADATA;
   op->data.recv_initial_metadata.recv_initial_metadata = &initial_metadata_recv;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_MESSAGE;
   op->data.recv_message.recv_message = &response_payload_recv;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_STATUS_ON_CLIENT;
   op->data.recv_status_on_client.trailing_metadata = &trailing_metadata_recv;
   op->data.recv_status_on_client.status = &status;
   op->data.recv_status_on_client.status_details = &details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), NULL);
+  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   error =
@@ -193,14 +193,14 @@ static void request_response_with_payload(grpc_end2end_test_config config,
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
   op->data.send_initial_metadata.count = 0;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_MESSAGE;
   op->data.recv_message.recv_message = &request_payload_recv;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(102), NULL);
+  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(102), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   CQ_EXPECT_COMPLETION(cqv, tag(102), 1);
@@ -211,12 +211,12 @@ static void request_response_with_payload(grpc_end2end_test_config config,
   op->op = GRPC_OP_RECV_CLOSE_ON_SERVER;
   op->data.recv_close_on_server.cancelled = &was_cancelled;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_MESSAGE;
   op->data.send_message.send_message = response_payload;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_STATUS_FROM_SERVER;
   op->data.send_status_from_server.trailing_metadata_count = 0;
@@ -224,9 +224,9 @@ static void request_response_with_payload(grpc_end2end_test_config config,
   grpc_slice status_details = grpc_slice_from_static_string("xyz");
   op->data.send_status_from_server.status_details = &status_details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(103), NULL);
+  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(103), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   CQ_EXPECT_COMPLETION(cqv, tag(103), 1);
@@ -266,10 +266,10 @@ static void test_invoke_request_response_with_payload(
     grpc_end2end_test_config config) {
   grpc_channel_args* client_args =
       grpc_channel_args_set_stream_compression_algorithm(
-          NULL, GRPC_STREAM_COMPRESS_GZIP);
+          nullptr, GRPC_STREAM_COMPRESS_GZIP);
   grpc_channel_args* server_args =
       grpc_channel_args_set_stream_compression_algorithm(
-          NULL, GRPC_STREAM_COMPRESS_GZIP);
+          nullptr, GRPC_STREAM_COMPRESS_GZIP);
   grpc_end2end_test_fixture f =
       begin_test(config, "test_invoke_request_response_with_payload",
                  client_args, server_args);
@@ -288,7 +288,7 @@ static void test_invoke_10_request_response_with_payload(
     grpc_end2end_test_config config) {
   int i;
   grpc_end2end_test_fixture f = begin_test(
-      config, "test_invoke_10_request_response_with_payload", NULL, NULL);
+      config, "test_invoke_10_request_response_with_payload", nullptr, nullptr);
   for (i = 0; i < 10; i++) {
     request_response_with_payload(config, f);
   }
diff --git a/test/core/end2end/tests/stream_compression_ping_pong_streaming.cc b/test/core/end2end/tests/stream_compression_ping_pong_streaming.cc
index a5321bfc61..1cd87c9d9c 100644
--- a/test/core/end2end/tests/stream_compression_ping_pong_streaming.cc
+++ b/test/core/end2end/tests/stream_compression_ping_pong_streaming.cc
@@ -56,7 +56,7 @@ static gpr_timespec five_seconds_from_now(void) {
 static void drain_cq(grpc_completion_queue* cq) {
   grpc_event ev;
   do {
-    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), NULL);
+    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), nullptr);
   } while (ev.type != GRPC_QUEUE_SHUTDOWN);
 }
 
@@ -65,16 +65,16 @@ static void shutdown_server(grpc_end2end_test_fixture* f) {
   grpc_server_shutdown_and_notify(f->server, f->shutdown_cq, tag(1000));
   GPR_ASSERT(grpc_completion_queue_pluck(f->shutdown_cq, tag(1000),
                                          grpc_timeout_seconds_to_deadline(5),
-                                         NULL)
+                                         nullptr)
                  .type == GRPC_OP_COMPLETE);
   grpc_server_destroy(f->server);
-  f->server = NULL;
+  f->server = nullptr;
 }
 
 static void shutdown_client(grpc_end2end_test_fixture* f) {
   if (!f->client) return;
   grpc_channel_destroy(f->client);
-  f->client = NULL;
+  f->client = nullptr;
 }
 
 static void end_test(grpc_end2end_test_fixture* f) {
@@ -92,10 +92,10 @@ static void test_pingpong_streaming(grpc_end2end_test_config config,
                                     int messages) {
   grpc_channel_args* client_args =
       grpc_channel_args_set_stream_compression_algorithm(
-          NULL, GRPC_STREAM_COMPRESS_GZIP);
+          nullptr, GRPC_STREAM_COMPRESS_GZIP);
   grpc_channel_args* server_args =
       grpc_channel_args_set_stream_compression_algorithm(
-          NULL, GRPC_STREAM_COMPRESS_GZIP);
+          nullptr, GRPC_STREAM_COMPRESS_GZIP);
   grpc_end2end_test_fixture f =
       begin_test(config, "test_pingpong_streaming", client_args, server_args);
   grpc_call* c;
@@ -123,10 +123,10 @@ static void test_pingpong_streaming(grpc_end2end_test_config config,
 
   gpr_timespec deadline = five_seconds_from_now();
   c = grpc_channel_create_call(
-      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+      f.client, nullptr, GRPC_PROPAGATE_DEFAULTS, f.cq,
       grpc_slice_from_static_string("/foo"),
       get_host_override_slice("foo.test.google.fr:1234", config), deadline,
-      NULL);
+      nullptr);
   GPR_ASSERT(c);
 
   grpc_metadata_array_init(&initial_metadata_recv);
@@ -139,21 +139,21 @@ static void test_pingpong_streaming(grpc_end2end_test_config config,
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
   op->data.send_initial_metadata.count = 0;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_INITIAL_METADATA;
   op->data.recv_initial_metadata.recv_initial_metadata = &initial_metadata_recv;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_STATUS_ON_CLIENT;
   op->data.recv_status_on_client.trailing_metadata = &trailing_metadata_recv;
   op->data.recv_status_on_client.status = &status;
   op->data.recv_status_on_client.status_details = &details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), NULL);
+  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   error =
@@ -168,14 +168,14 @@ static void test_pingpong_streaming(grpc_end2end_test_config config,
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
   op->data.send_initial_metadata.count = 0;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_CLOSE_ON_SERVER;
   op->data.recv_close_on_server.cancelled = &was_cancelled;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(101), NULL);
+  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(101), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   for (i = 0; i < messages; i++) {
@@ -187,14 +187,14 @@ static void test_pingpong_streaming(grpc_end2end_test_config config,
     op->op = GRPC_OP_SEND_MESSAGE;
     op->data.send_message.send_message = request_payload;
     op->flags = 0;
-    op->reserved = NULL;
+    op->reserved = nullptr;
     op++;
     op->op = GRPC_OP_RECV_MESSAGE;
     op->data.recv_message.recv_message = &response_payload_recv;
     op->flags = 0;
-    op->reserved = NULL;
+    op->reserved = nullptr;
     op++;
-    error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(2), NULL);
+    error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(2), nullptr);
     GPR_ASSERT(GRPC_CALL_OK == error);
 
     memset(ops, 0, sizeof(ops));
@@ -202,9 +202,9 @@ static void test_pingpong_streaming(grpc_end2end_test_config config,
     op->op = GRPC_OP_RECV_MESSAGE;
     op->data.recv_message.recv_message = &request_payload_recv;
     op->flags = 0;
-    op->reserved = NULL;
+    op->reserved = nullptr;
     op++;
-    error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(102), NULL);
+    error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(102), nullptr);
     GPR_ASSERT(GRPC_CALL_OK == error);
     CQ_EXPECT_COMPLETION(cqv, tag(102), 1);
     cq_verify(cqv);
@@ -214,9 +214,9 @@ static void test_pingpong_streaming(grpc_end2end_test_config config,
     op->op = GRPC_OP_SEND_MESSAGE;
     op->data.send_message.send_message = response_payload;
     op->flags = 0;
-    op->reserved = NULL;
+    op->reserved = nullptr;
     op++;
-    error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(103), NULL);
+    error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(103), nullptr);
     GPR_ASSERT(GRPC_CALL_OK == error);
     CQ_EXPECT_COMPLETION(cqv, tag(103), 1);
     CQ_EXPECT_COMPLETION(cqv, tag(2), 1);
@@ -235,9 +235,9 @@ static void test_pingpong_streaming(grpc_end2end_test_config config,
   op = ops;
   op->op = GRPC_OP_SEND_CLOSE_FROM_CLIENT;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(3), NULL);
+  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(3), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   memset(ops, 0, sizeof(ops));
@@ -248,9 +248,9 @@ static void test_pingpong_streaming(grpc_end2end_test_config config,
   grpc_slice status_details = grpc_slice_from_static_string("xyz");
   op->data.send_status_from_server.status_details = &status_details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(104), NULL);
+  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(104), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   CQ_EXPECT_COMPLETION(cqv, tag(1), 1);
diff --git a/test/core/end2end/tests/streaming_error_response.cc b/test/core/end2end/tests/streaming_error_response.cc
index f87fd2c4c3..d011b6aa36 100644
--- a/test/core/end2end/tests/streaming_error_response.cc
+++ b/test/core/end2end/tests/streaming_error_response.cc
@@ -58,7 +58,7 @@ static gpr_timespec five_seconds_from_now(void) {
 static void drain_cq(grpc_completion_queue* cq) {
   grpc_event ev;
   do {
-    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), NULL);
+    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), nullptr);
   } while (ev.type != GRPC_QUEUE_SHUTDOWN);
 }
 
@@ -67,16 +67,16 @@ static void shutdown_server(grpc_end2end_test_fixture* f) {
   grpc_server_shutdown_and_notify(f->server, f->shutdown_cq, tag(1000));
   GPR_ASSERT(grpc_completion_queue_pluck(f->shutdown_cq, tag(1000),
                                          grpc_timeout_seconds_to_deadline(5),
-                                         NULL)
+                                         nullptr)
                  .type == GRPC_OP_COMPLETE);
   grpc_server_destroy(f->server);
-  f->server = NULL;
+  f->server = nullptr;
 }
 
 static void shutdown_client(grpc_end2end_test_fixture* f) {
   if (!f->client) return;
   grpc_channel_destroy(f->client);
-  f->client = NULL;
+  f->client = nullptr;
 }
 
 static void end_test(grpc_end2end_test_fixture* f) {
@@ -100,15 +100,15 @@ static void test(grpc_end2end_test_config config, bool request_status_early) {
   grpc_byte_buffer* response_payload2 =
       grpc_raw_byte_buffer_create(&response_payload2_slice, 1);
   grpc_end2end_test_fixture f = begin_test(config, "streaming_error_response",
-                                           NULL, NULL, request_status_early);
+                                           nullptr, nullptr, request_status_early);
   cq_verifier* cqv = cq_verifier_create(f.cq);
   grpc_op ops[6];
   grpc_op* op;
   grpc_metadata_array initial_metadata_recv;
   grpc_metadata_array trailing_metadata_recv;
   grpc_metadata_array request_metadata_recv;
-  grpc_byte_buffer* response_payload1_recv = NULL;
-  grpc_byte_buffer* response_payload2_recv = NULL;
+  grpc_byte_buffer* response_payload1_recv = nullptr;
+  grpc_byte_buffer* response_payload2_recv = nullptr;
   grpc_call_details call_details;
   grpc_status_code status;
   grpc_call_error error;
@@ -117,10 +117,10 @@ static void test(grpc_end2end_test_config config, bool request_status_early) {
 
   gpr_timespec deadline = five_seconds_from_now();
   c = grpc_channel_create_call(
-      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+      f.client, nullptr, GRPC_PROPAGATE_DEFAULTS, f.cq,
       grpc_slice_from_static_string("/foo"),
       get_host_override_slice("foo.test.google.fr:1234", config), deadline,
-      NULL);
+      nullptr);
   GPR_ASSERT(c);
 
   grpc_metadata_array_init(&initial_metadata_recv);
@@ -148,7 +148,7 @@ static void test(grpc_end2end_test_config config, bool request_status_early) {
     op->data.recv_status_on_client.status_details = &details;
     op++;
   }
-  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), NULL);
+  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   GPR_ASSERT(GRPC_CALL_OK == grpc_server_request_call(
@@ -165,7 +165,7 @@ static void test(grpc_end2end_test_config config, bool request_status_early) {
   op->op = GRPC_OP_SEND_MESSAGE;
   op->data.send_message.send_message = response_payload1;
   op++;
-  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(102), NULL);
+  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(102), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   CQ_EXPECT_COMPLETION(cqv, tag(102), 1);
@@ -179,7 +179,7 @@ static void test(grpc_end2end_test_config config, bool request_status_early) {
   op->op = GRPC_OP_SEND_MESSAGE;
   op->data.send_message.send_message = response_payload2;
   op++;
-  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(103), NULL);
+  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(103), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   CQ_EXPECT_COMPLETION(cqv, tag(103), 1);
@@ -190,7 +190,7 @@ static void test(grpc_end2end_test_config config, bool request_status_early) {
     op->op = GRPC_OP_RECV_MESSAGE;
     op->data.recv_message.recv_message = &response_payload2_recv;
     op++;
-    error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(2), NULL);
+    error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(2), nullptr);
     GPR_ASSERT(GRPC_CALL_OK == error);
 
     CQ_EXPECT_COMPLETION(cqv, tag(2), 1);
@@ -208,7 +208,7 @@ static void test(grpc_end2end_test_config config, bool request_status_early) {
   grpc_slice status_details = grpc_slice_from_static_string("xyz");
   op->data.send_status_from_server.status_details = &status_details;
   op++;
-  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(104), NULL);
+  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(104), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   CQ_EXPECT_COMPLETION(cqv, tag(104), 1);
@@ -225,14 +225,14 @@ static void test(grpc_end2end_test_config config, bool request_status_early) {
     op->data.recv_status_on_client.status = &status;
     op->data.recv_status_on_client.status_details = &details;
     op++;
-    error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(3), NULL);
+    error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(3), nullptr);
     GPR_ASSERT(GRPC_CALL_OK == error);
 
     CQ_EXPECT_COMPLETION(cqv, tag(3), 1);
     cq_verify(cqv);
 
-    GPR_ASSERT(response_payload1_recv != NULL);
-    GPR_ASSERT(response_payload2_recv != NULL);
+    GPR_ASSERT(response_payload1_recv != nullptr);
+    GPR_ASSERT(response_payload2_recv != nullptr);
   }
 
   GPR_ASSERT(status == GRPC_STATUS_FAILED_PRECONDITION);
diff --git a/test/core/end2end/tests/trailing_metadata.cc b/test/core/end2end/tests/trailing_metadata.cc
index 0da02a56db..8a6be7a892 100644
--- a/test/core/end2end/tests/trailing_metadata.cc
+++ b/test/core/end2end/tests/trailing_metadata.cc
@@ -53,7 +53,7 @@ static gpr_timespec five_seconds_from_now(void) {
 static void drain_cq(grpc_completion_queue* cq) {
   grpc_event ev;
   do {
-    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), NULL);
+    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), nullptr);
   } while (ev.type != GRPC_QUEUE_SHUTDOWN);
 }
 
@@ -62,16 +62,16 @@ static void shutdown_server(grpc_end2end_test_fixture* f) {
   grpc_server_shutdown_and_notify(f->server, f->shutdown_cq, tag(1000));
   GPR_ASSERT(grpc_completion_queue_pluck(f->shutdown_cq, tag(1000),
                                          grpc_timeout_seconds_to_deadline(5),
-                                         NULL)
+                                         nullptr)
                  .type == GRPC_OP_COMPLETE);
   grpc_server_destroy(f->server);
-  f->server = NULL;
+  f->server = nullptr;
 }
 
 static void shutdown_client(grpc_end2end_test_fixture* f) {
   if (!f->client) return;
   grpc_channel_destroy(f->client);
-  f->client = NULL;
+  f->client = nullptr;
 }
 
 static void end_test(grpc_end2end_test_fixture* f) {
@@ -100,37 +100,37 @@ static void test_request_response_with_metadata_and_payload(
   grpc_metadata meta_c[2] = {{grpc_slice_from_static_string("key1"),
                               grpc_slice_from_static_string("val1"),
                               0,
-                              {{NULL, NULL, NULL, NULL}}},
+                              {{nullptr, nullptr, nullptr, nullptr}}},
                              {grpc_slice_from_static_string("key2"),
                               grpc_slice_from_static_string("val2"),
                               0,
-                              {{NULL, NULL, NULL, NULL}}}};
+                              {{nullptr, nullptr, nullptr, nullptr}}}};
   grpc_metadata meta_s[2] = {{grpc_slice_from_static_string("key3"),
                               grpc_slice_from_static_string("val3"),
                               0,
-                              {{NULL, NULL, NULL, NULL}}},
+                              {{nullptr, nullptr, nullptr, nullptr}}},
                              {grpc_slice_from_static_string("key4"),
                               grpc_slice_from_static_string("val4"),
                               0,
-                              {{NULL, NULL, NULL, NULL}}}};
+                              {{nullptr, nullptr, nullptr, nullptr}}}};
   grpc_metadata meta_t[2] = {{grpc_slice_from_static_string("key5"),
                               grpc_slice_from_static_string("val5"),
                               0,
-                              {{NULL, NULL, NULL, NULL}}},
+                              {{nullptr, nullptr, nullptr, nullptr}}},
                              {grpc_slice_from_static_string("key6"),
                               grpc_slice_from_static_string("val6"),
                               0,
-                              {{NULL, NULL, NULL, NULL}}}};
+                              {{nullptr, nullptr, nullptr, nullptr}}}};
   grpc_end2end_test_fixture f = begin_test(
-      config, "test_request_response_with_metadata_and_payload", NULL, NULL);
+      config, "test_request_response_with_metadata_and_payload", nullptr, nullptr);
   cq_verifier* cqv = cq_verifier_create(f.cq);
   grpc_op ops[6];
   grpc_op* op;
   grpc_metadata_array initial_metadata_recv;
   grpc_metadata_array trailing_metadata_recv;
   grpc_metadata_array request_metadata_recv;
-  grpc_byte_buffer* request_payload_recv = NULL;
-  grpc_byte_buffer* response_payload_recv = NULL;
+  grpc_byte_buffer* request_payload_recv = nullptr;
+  grpc_byte_buffer* response_payload_recv = nullptr;
   grpc_call_details call_details;
   grpc_status_code status;
   grpc_call_error error;
@@ -139,10 +139,10 @@ static void test_request_response_with_metadata_and_payload(
 
   gpr_timespec deadline = five_seconds_from_now();
   c = grpc_channel_create_call(
-      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+      f.client, nullptr, GRPC_PROPAGATE_DEFAULTS, f.cq,
       grpc_slice_from_static_string("/foo"),
       get_host_override_slice("foo.test.google.fr:1234", config), deadline,
-      NULL);
+      nullptr);
   GPR_ASSERT(c);
 
   grpc_metadata_array_init(&initial_metadata_recv);
@@ -156,35 +156,35 @@ static void test_request_response_with_metadata_and_payload(
   op->data.send_initial_metadata.count = 2;
   op->data.send_initial_metadata.metadata = meta_c;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_MESSAGE;
   op->data.send_message.send_message = request_payload;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_CLOSE_FROM_CLIENT;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_INITIAL_METADATA;
   op->data.recv_initial_metadata.recv_initial_metadata = &initial_metadata_recv;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_MESSAGE;
   op->data.recv_message.recv_message = &response_payload_recv;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_STATUS_ON_CLIENT;
   op->data.recv_status_on_client.trailing_metadata = &trailing_metadata_recv;
   op->data.recv_status_on_client.status = &status;
   op->data.recv_status_on_client.status_details = &details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), NULL);
+  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   error =
@@ -200,14 +200,14 @@ static void test_request_response_with_metadata_and_payload(
   op->data.send_initial_metadata.count = 2;
   op->data.send_initial_metadata.metadata = meta_s;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_MESSAGE;
   op->data.recv_message.recv_message = &request_payload_recv;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(102), NULL);
+  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(102), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   CQ_EXPECT_COMPLETION(cqv, tag(102), 1);
@@ -218,12 +218,12 @@ static void test_request_response_with_metadata_and_payload(
   op->op = GRPC_OP_RECV_CLOSE_ON_SERVER;
   op->data.recv_close_on_server.cancelled = &was_cancelled;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_MESSAGE;
   op->data.send_message.send_message = response_payload;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_STATUS_FROM_SERVER;
   op->data.send_status_from_server.trailing_metadata_count = 2;
@@ -232,9 +232,9 @@ static void test_request_response_with_metadata_and_payload(
   grpc_slice status_details = grpc_slice_from_static_string("xyz");
   op->data.send_status_from_server.status_details = &status_details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(103), NULL);
+  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(103), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   CQ_EXPECT_COMPLETION(cqv, tag(103), 1);
diff --git a/test/core/end2end/tests/workaround_cronet_compression.cc b/test/core/end2end/tests/workaround_cronet_compression.cc
index 8f8ca16a9e..71d461f469 100644
--- a/test/core/end2end/tests/workaround_cronet_compression.cc
+++ b/test/core/end2end/tests/workaround_cronet_compression.cc
@@ -61,7 +61,7 @@ static gpr_timespec five_seconds_from_now(void) {
 static void drain_cq(grpc_completion_queue* cq) {
   grpc_event ev;
   do {
-    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), NULL);
+    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), nullptr);
   } while (ev.type != GRPC_QUEUE_SHUTDOWN);
 }
 
@@ -70,16 +70,16 @@ static void shutdown_server(grpc_end2end_test_fixture* f) {
   grpc_server_shutdown_and_notify(f->server, f->shutdown_cq, tag(1000));
   GPR_ASSERT(grpc_completion_queue_pluck(f->shutdown_cq, tag(1000),
                                          grpc_timeout_seconds_to_deadline(5),
-                                         NULL)
+                                         nullptr)
                  .type == GRPC_OP_COMPLETE);
   grpc_server_destroy(f->server);
-  f->server = NULL;
+  f->server = nullptr;
 }
 
 static void shutdown_client(grpc_end2end_test_fixture* f) {
   if (!f->client) return;
   grpc_channel_destroy(f->client);
-  f->client = NULL;
+  f->client = nullptr;
 }
 
 static void end_test(grpc_end2end_test_fixture* f) {
@@ -114,7 +114,7 @@ static void request_with_payload_template(
   grpc_metadata_array initial_metadata_recv;
   grpc_metadata_array trailing_metadata_recv;
   grpc_metadata_array request_metadata_recv;
-  grpc_byte_buffer* request_payload_recv = NULL;
+  grpc_byte_buffer* request_payload_recv = nullptr;
   grpc_byte_buffer* response_payload;
   grpc_byte_buffer* response_payload_recv;
   grpc_call_details call_details;
@@ -137,9 +137,9 @@ static void request_with_payload_template(
       grpc_slice_from_copied_string(response_str);
 
   client_args = grpc_channel_args_set_compression_algorithm(
-      NULL, default_client_channel_compression_algorithm);
+      nullptr, default_client_channel_compression_algorithm);
   server_args = grpc_channel_args_set_compression_algorithm(
-      NULL, default_server_channel_compression_algorithm);
+      nullptr, default_server_channel_compression_algorithm);
 
   if (user_agent_override) {
     grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
@@ -158,10 +158,10 @@ static void request_with_payload_template(
 
   gpr_timespec deadline = five_seconds_from_now();
   c = grpc_channel_create_call(
-      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+      f.client, nullptr, GRPC_PROPAGATE_DEFAULTS, f.cq,
       grpc_slice_from_static_string("/foo"),
       get_host_override_slice("foo.test.google.fr:1234", config), deadline,
-      NULL);
+      nullptr);
   GPR_ASSERT(c);
 
   grpc_metadata_array_init(&initial_metadata_recv);
@@ -172,28 +172,28 @@ static void request_with_payload_template(
   memset(ops, 0, sizeof(ops));
   op = ops;
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
-  if (client_init_metadata != NULL) {
+  if (client_init_metadata != nullptr) {
     op->data.send_initial_metadata.count = 1;
     op->data.send_initial_metadata.metadata = client_init_metadata;
   } else {
     op->data.send_initial_metadata.count = 0;
   }
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_INITIAL_METADATA;
   op->data.recv_initial_metadata.recv_initial_metadata = &initial_metadata_recv;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_STATUS_ON_CLIENT;
   op->data.recv_status_on_client.trailing_metadata = &trailing_metadata_recv;
   op->data.recv_status_on_client.status = &status;
   op->data.recv_status_on_client.status_details = &details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), NULL);
+  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   error =
@@ -222,14 +222,14 @@ static void request_with_payload_template(
         server_compression_level;
   }
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_CLOSE_ON_SERVER;
   op->data.recv_close_on_server.cancelled = &was_cancelled;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(101), NULL);
+  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(101), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   for (int i = 0; i < 2; i++) {
@@ -241,14 +241,14 @@ static void request_with_payload_template(
     op->op = GRPC_OP_SEND_MESSAGE;
     op->data.send_message.send_message = request_payload;
     op->flags = client_send_flags_bitmask;
-    op->reserved = NULL;
+    op->reserved = nullptr;
     op++;
     op->op = GRPC_OP_RECV_MESSAGE;
     op->data.recv_message.recv_message = &response_payload_recv;
     op->flags = 0;
-    op->reserved = NULL;
+    op->reserved = nullptr;
     op++;
-    error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(2), NULL);
+    error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(2), nullptr);
     GPR_ASSERT(GRPC_CALL_OK == error);
 
     memset(ops, 0, sizeof(ops));
@@ -256,9 +256,9 @@ static void request_with_payload_template(
     op->op = GRPC_OP_RECV_MESSAGE;
     op->data.recv_message.recv_message = &request_payload_recv;
     op->flags = 0;
-    op->reserved = NULL;
+    op->reserved = nullptr;
     op++;
-    error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(102), NULL);
+    error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(102), nullptr);
     GPR_ASSERT(GRPC_CALL_OK == error);
     CQ_EXPECT_COMPLETION(cqv, tag(102), 1);
     cq_verify(cqv);
@@ -273,9 +273,9 @@ static void request_with_payload_template(
     op->op = GRPC_OP_SEND_MESSAGE;
     op->data.send_message.send_message = response_payload;
     op->flags = 0;
-    op->reserved = NULL;
+    op->reserved = nullptr;
     op++;
-    error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(103), NULL);
+    error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(103), nullptr);
     GPR_ASSERT(GRPC_CALL_OK == error);
     CQ_EXPECT_COMPLETION(cqv, tag(103), 1);
     CQ_EXPECT_COMPLETION(cqv, tag(2), 1);
@@ -306,9 +306,9 @@ static void request_with_payload_template(
   op = ops;
   op->op = GRPC_OP_SEND_CLOSE_FROM_CLIENT;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(3), NULL);
+  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(3), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   memset(ops, 0, sizeof(ops));
@@ -319,9 +319,9 @@ static void request_with_payload_template(
   grpc_slice status_details = grpc_slice_from_static_string("xyz");
   op->data.send_status_from_server.status_details = &status_details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(104), NULL);
+  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(104), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   CQ_EXPECT_COMPLETION(cqv, tag(1), 1);
@@ -365,7 +365,7 @@ typedef struct workaround_cronet_compression_config {
 } workaround_cronet_compression_config;
 
 static workaround_cronet_compression_config workaround_configs[] = {
-    {NULL, GRPC_COMPRESS_GZIP},
+    {nullptr, GRPC_COMPRESS_GZIP},
     {const_cast<char*>(
          "grpc-objc/1.3.0-dev grpc-c/3.0.0-dev (ios; cronet_http; gentle)"),
      GRPC_COMPRESS_NONE},
@@ -384,7 +384,7 @@ static void test_workaround_cronet_compression(
     request_with_payload_template(
         config, "test_invoke_request_with_compressed_payload", 0,
         GRPC_COMPRESS_GZIP, GRPC_COMPRESS_GZIP, GRPC_COMPRESS_GZIP,
-        workaround_configs[i].expected_algorithm_from_server, NULL, false,
+        workaround_configs[i].expected_algorithm_from_server, nullptr, false,
         /* ignored */ GRPC_COMPRESS_LEVEL_NONE,
         workaround_configs[i].user_agent_override);
   }
diff --git a/test/core/end2end/tests/write_buffering.cc b/test/core/end2end/tests/write_buffering.cc
index 5e92e598b3..40821dd6f0 100644
--- a/test/core/end2end/tests/write_buffering.cc
+++ b/test/core/end2end/tests/write_buffering.cc
@@ -53,7 +53,7 @@ static gpr_timespec five_seconds_from_now(void) {
 static void drain_cq(grpc_completion_queue* cq) {
   grpc_event ev;
   do {
-    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), NULL);
+    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), nullptr);
   } while (ev.type != GRPC_QUEUE_SHUTDOWN);
 }
 
@@ -62,16 +62,16 @@ static void shutdown_server(grpc_end2end_test_fixture* f) {
   grpc_server_shutdown_and_notify(f->server, f->shutdown_cq, tag(1000));
   GPR_ASSERT(grpc_completion_queue_pluck(f->shutdown_cq, tag(1000),
                                          grpc_timeout_seconds_to_deadline(5),
-                                         NULL)
+                                         nullptr)
                  .type == GRPC_OP_COMPLETE);
   grpc_server_destroy(f->server);
-  f->server = NULL;
+  f->server = nullptr;
 }
 
 static void shutdown_client(grpc_end2end_test_fixture* f) {
   if (!f->client) return;
   grpc_channel_destroy(f->client);
-  f->client = NULL;
+  f->client = nullptr;
 }
 
 static void end_test(grpc_end2end_test_fixture* f) {
@@ -96,15 +96,15 @@ static void test_invoke_request_with_payload(grpc_end2end_test_config config) {
   grpc_byte_buffer* request_payload2 =
       grpc_raw_byte_buffer_create(&request_payload_slice2, 1);
   grpc_end2end_test_fixture f =
-      begin_test(config, "test_invoke_request_with_payload", NULL, NULL);
+      begin_test(config, "test_invoke_request_with_payload", nullptr, nullptr);
   cq_verifier* cqv = cq_verifier_create(f.cq);
   grpc_op ops[6];
   grpc_op* op;
   grpc_metadata_array initial_metadata_recv;
   grpc_metadata_array trailing_metadata_recv;
   grpc_metadata_array request_metadata_recv;
-  grpc_byte_buffer* request_payload_recv1 = NULL;
-  grpc_byte_buffer* request_payload_recv2 = NULL;
+  grpc_byte_buffer* request_payload_recv1 = nullptr;
+  grpc_byte_buffer* request_payload_recv2 = nullptr;
   grpc_call_details call_details;
   grpc_status_code status;
   grpc_call_error error;
@@ -113,10 +113,10 @@ static void test_invoke_request_with_payload(grpc_end2end_test_config config) {
 
   gpr_timespec deadline = five_seconds_from_now();
   c = grpc_channel_create_call(
-      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+      f.client, nullptr, GRPC_PROPAGATE_DEFAULTS, f.cq,
       grpc_slice_from_static_string("/foo"),
       get_host_override_slice("foo.test.google.fr:1234", config), deadline,
-      NULL);
+      nullptr);
   GPR_ASSERT(c);
 
   grpc_metadata_array_init(&initial_metadata_recv);
@@ -129,7 +129,7 @@ static void test_invoke_request_with_payload(grpc_end2end_test_config config) {
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
   op->data.send_initial_metadata.count = 0;
   op++;
-  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), NULL);
+  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   memset(ops, 0, sizeof(ops));
@@ -137,9 +137,9 @@ static void test_invoke_request_with_payload(grpc_end2end_test_config config) {
   op->op = GRPC_OP_RECV_INITIAL_METADATA;
   op->data.recv_initial_metadata.recv_initial_metadata = &initial_metadata_recv;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(2), NULL);
+  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(2), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   GPR_ASSERT(GRPC_CALL_OK == grpc_server_request_call(
@@ -155,7 +155,7 @@ static void test_invoke_request_with_payload(grpc_end2end_test_config config) {
   op->data.send_message.send_message = request_payload1;
   op->flags = GRPC_WRITE_BUFFER_HINT;
   op++;
-  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(3), NULL);
+  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(3), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   memset(ops, 0, sizeof(ops));
@@ -163,7 +163,7 @@ static void test_invoke_request_with_payload(grpc_end2end_test_config config) {
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
   op->data.send_initial_metadata.count = 0;
   op++;
-  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(102), NULL);
+  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(102), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   /* recv message should not succeed yet - it's buffered at the client still */
@@ -172,7 +172,7 @@ static void test_invoke_request_with_payload(grpc_end2end_test_config config) {
   op->op = GRPC_OP_RECV_MESSAGE;
   op->data.recv_message.recv_message = &request_payload_recv1;
   op++;
-  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(103), NULL);
+  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(103), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   CQ_EXPECT_COMPLETION(cqv, tag(2), true);
@@ -187,7 +187,7 @@ static void test_invoke_request_with_payload(grpc_end2end_test_config config) {
   op->data.send_message.send_message = request_payload2;
   op->flags = 0;
   op++;
-  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(4), NULL);
+  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(4), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   /* now the first send should match up with the first recv */
@@ -201,7 +201,7 @@ static void test_invoke_request_with_payload(grpc_end2end_test_config config) {
   op->op = GRPC_OP_RECV_MESSAGE;
   op->data.recv_message.recv_message = &request_payload_recv2;
   op++;
-  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(104), NULL);
+  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(104), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   CQ_EXPECT_COMPLETION(cqv, tag(104), true);
@@ -211,23 +211,23 @@ static void test_invoke_request_with_payload(grpc_end2end_test_config config) {
   op = ops;
   op->op = GRPC_OP_SEND_CLOSE_FROM_CLIENT;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_RECV_STATUS_ON_CLIENT;
   op->data.recv_status_on_client.trailing_metadata = &trailing_metadata_recv;
   op->data.recv_status_on_client.status = &status;
   op->data.recv_status_on_client.status_details = &details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(4), NULL);
+  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(4), nullptr);
 
   memset(ops, 0, sizeof(ops));
   op = ops;
   op->op = GRPC_OP_RECV_CLOSE_ON_SERVER;
   op->data.recv_close_on_server.cancelled = &was_cancelled;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_STATUS_FROM_SERVER;
   op->data.send_status_from_server.trailing_metadata_count = 0;
@@ -235,9 +235,9 @@ static void test_invoke_request_with_payload(grpc_end2end_test_config config) {
   grpc_slice status_details = grpc_slice_from_static_string("xyz");
   op->data.send_status_from_server.status_details = &status_details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(105), NULL);
+  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(105), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   CQ_EXPECT_COMPLETION(cqv, tag(105), 1);
diff --git a/test/core/end2end/tests/write_buffering_at_end.cc b/test/core/end2end/tests/write_buffering_at_end.cc
index 01dacdfd12..1b9dc9632b 100644
--- a/test/core/end2end/tests/write_buffering_at_end.cc
+++ b/test/core/end2end/tests/write_buffering_at_end.cc
@@ -53,7 +53,7 @@ static gpr_timespec five_seconds_from_now(void) {
 static void drain_cq(grpc_completion_queue* cq) {
   grpc_event ev;
   do {
-    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), NULL);
+    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), nullptr);
   } while (ev.type != GRPC_QUEUE_SHUTDOWN);
 }
 
@@ -62,16 +62,16 @@ static void shutdown_server(grpc_end2end_test_fixture* f) {
   grpc_server_shutdown_and_notify(f->server, f->shutdown_cq, tag(1000));
   GPR_ASSERT(grpc_completion_queue_pluck(f->shutdown_cq, tag(1000),
                                          grpc_timeout_seconds_to_deadline(5),
-                                         NULL)
+                                         nullptr)
                  .type == GRPC_OP_COMPLETE);
   grpc_server_destroy(f->server);
-  f->server = NULL;
+  f->server = nullptr;
 }
 
 static void shutdown_client(grpc_end2end_test_fixture* f) {
   if (!f->client) return;
   grpc_channel_destroy(f->client);
-  f->client = NULL;
+  f->client = nullptr;
 }
 
 static void end_test(grpc_end2end_test_fixture* f) {
@@ -93,15 +93,15 @@ static void test_invoke_request_with_payload(grpc_end2end_test_config config) {
   grpc_byte_buffer* request_payload =
       grpc_raw_byte_buffer_create(&request_payload_slice, 1);
   grpc_end2end_test_fixture f =
-      begin_test(config, "test_invoke_request_with_payload", NULL, NULL);
+      begin_test(config, "test_invoke_request_with_payload", nullptr, nullptr);
   cq_verifier* cqv = cq_verifier_create(f.cq);
   grpc_op ops[6];
   grpc_op* op;
   grpc_metadata_array initial_metadata_recv;
   grpc_metadata_array trailing_metadata_recv;
   grpc_metadata_array request_metadata_recv;
-  grpc_byte_buffer* request_payload_recv1 = NULL;
-  grpc_byte_buffer* request_payload_recv2 = NULL;
+  grpc_byte_buffer* request_payload_recv1 = nullptr;
+  grpc_byte_buffer* request_payload_recv2 = nullptr;
   grpc_call_details call_details;
   grpc_status_code status;
   grpc_call_error error;
@@ -110,10 +110,10 @@ static void test_invoke_request_with_payload(grpc_end2end_test_config config) {
 
   gpr_timespec deadline = five_seconds_from_now();
   c = grpc_channel_create_call(
-      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+      f.client, nullptr, GRPC_PROPAGATE_DEFAULTS, f.cq,
       grpc_slice_from_static_string("/foo"),
       get_host_override_slice("foo.test.google.fr:1234", config), deadline,
-      NULL);
+      nullptr);
   GPR_ASSERT(c);
 
   grpc_metadata_array_init(&initial_metadata_recv);
@@ -126,7 +126,7 @@ static void test_invoke_request_with_payload(grpc_end2end_test_config config) {
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
   op->data.send_initial_metadata.count = 0;
   op++;
-  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), NULL);
+  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   memset(ops, 0, sizeof(ops));
@@ -134,9 +134,9 @@ static void test_invoke_request_with_payload(grpc_end2end_test_config config) {
   op->op = GRPC_OP_RECV_INITIAL_METADATA;
   op->data.recv_initial_metadata.recv_initial_metadata = &initial_metadata_recv;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(2), NULL);
+  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(2), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   GPR_ASSERT(GRPC_CALL_OK == grpc_server_request_call(
@@ -152,7 +152,7 @@ static void test_invoke_request_with_payload(grpc_end2end_test_config config) {
   op->data.send_message.send_message = request_payload;
   op->flags = GRPC_WRITE_BUFFER_HINT;
   op++;
-  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(3), NULL);
+  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(3), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   memset(ops, 0, sizeof(ops));
@@ -160,7 +160,7 @@ static void test_invoke_request_with_payload(grpc_end2end_test_config config) {
   op->op = GRPC_OP_SEND_INITIAL_METADATA;
   op->data.send_initial_metadata.count = 0;
   op++;
-  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(102), NULL);
+  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(102), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   /* recv message should not succeed yet - it's buffered at the client still */
@@ -169,7 +169,7 @@ static void test_invoke_request_with_payload(grpc_end2end_test_config config) {
   op->op = GRPC_OP_RECV_MESSAGE;
   op->data.recv_message.recv_message = &request_payload_recv1;
   op++;
-  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(103), NULL);
+  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(103), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   CQ_EXPECT_COMPLETION(cqv, tag(2), true);
@@ -182,7 +182,7 @@ static void test_invoke_request_with_payload(grpc_end2end_test_config config) {
   op = ops;
   op->op = GRPC_OP_SEND_CLOSE_FROM_CLIENT;
   op++;
-  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(4), NULL);
+  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(4), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   /* now the first send should match up with the first recv */
@@ -196,7 +196,7 @@ static void test_invoke_request_with_payload(grpc_end2end_test_config config) {
   op->op = GRPC_OP_RECV_MESSAGE;
   op->data.recv_message.recv_message = &request_payload_recv2;
   op++;
-  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(104), NULL);
+  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(104), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   CQ_EXPECT_COMPLETION(cqv, tag(104), true);
@@ -209,16 +209,16 @@ static void test_invoke_request_with_payload(grpc_end2end_test_config config) {
   op->data.recv_status_on_client.status = &status;
   op->data.recv_status_on_client.status_details = &details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(4), NULL);
+  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(4), nullptr);
 
   memset(ops, 0, sizeof(ops));
   op = ops;
   op->op = GRPC_OP_RECV_CLOSE_ON_SERVER;
   op->data.recv_close_on_server.cancelled = &was_cancelled;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
   op->op = GRPC_OP_SEND_STATUS_FROM_SERVER;
   op->data.send_status_from_server.trailing_metadata_count = 0;
@@ -226,9 +226,9 @@ static void test_invoke_request_with_payload(grpc_end2end_test_config config) {
   grpc_slice status_details = grpc_slice_from_static_string("xyz");
   op->data.send_status_from_server.status_details = &status_details;
   op->flags = 0;
-  op->reserved = NULL;
+  op->reserved = nullptr;
   op++;
-  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(105), NULL);
+  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(105), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
 
   CQ_EXPECT_COMPLETION(cqv, tag(105), 1);
@@ -242,7 +242,7 @@ static void test_invoke_request_with_payload(grpc_end2end_test_config config) {
                                 config);
   GPR_ASSERT(was_cancelled == 0);
   GPR_ASSERT(byte_buffer_eq_string(request_payload_recv1, "hello world"));
-  GPR_ASSERT(request_payload_recv2 == NULL);
+  GPR_ASSERT(request_payload_recv2 == nullptr);
 
   grpc_slice_unref(details);
   grpc_metadata_array_destroy(&initial_metadata_recv);