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

11 files changed, 169 insertions, 169 deletions

diff --git a/test/core/bad_client/bad_client.cc b/test/core/bad_client/bad_client.cc
index b1944425ba..c8bd005d5c 100644
--- a/test/core/bad_client/bad_client.cc
+++ b/test/core/bad_client/bad_client.cc
@@ -58,7 +58,7 @@ static void done_write(grpc_exec_ctx* exec_ctx, void* arg, grpc_error* error) {
 static void server_setup_transport(void* ts, grpc_transport* transport) {
   thd_args* a = (thd_args*)ts;
   grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
-  grpc_server_setup_transport(&exec_ctx, a->server, transport, NULL,
+  grpc_server_setup_transport(&exec_ctx, a->server, transport, nullptr,
                               grpc_server_get_channel_args(a->server));
   grpc_exec_ctx_finish(&exec_ctx);
 }
@@ -101,23 +101,23 @@ void grpc_run_bad_client_test(
   grpc_init();
 
   /* Create endpoints */
-  sfd = grpc_iomgr_create_endpoint_pair("fixture", NULL);
+  sfd = grpc_iomgr_create_endpoint_pair("fixture", nullptr);
 
   /* Create server, completion events */
-  a.server = grpc_server_create(NULL, NULL);
-  a.cq = grpc_completion_queue_create_for_next(NULL);
+  a.server = grpc_server_create(nullptr, nullptr);
+  a.cq = grpc_completion_queue_create_for_next(nullptr);
   gpr_event_init(&a.done_thd);
   gpr_event_init(&a.done_write);
   a.validator = server_validator;
-  grpc_server_register_completion_queue(a.server, a.cq, NULL);
+  grpc_server_register_completion_queue(a.server, a.cq, nullptr);
   a.registered_method =
       grpc_server_register_method(a.server, GRPC_BAD_CLIENT_REGISTERED_METHOD,
                                   GRPC_BAD_CLIENT_REGISTERED_HOST,
                                   GRPC_SRM_PAYLOAD_READ_INITIAL_BYTE_BUFFER, 0);
   grpc_server_start(a.server);
-  transport = grpc_create_chttp2_transport(&exec_ctx, NULL, sfd.server, 0);
+  transport = grpc_create_chttp2_transport(&exec_ctx, nullptr, sfd.server, 0);
   server_setup_transport(&a, 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);
 
   /* Bind everything into the same pollset */
@@ -128,7 +128,7 @@ void grpc_run_bad_client_test(
   GPR_ASSERT(grpc_server_has_open_connections(a.server));
 
   /* Start validator */
-  gpr_thd_new(&id, thd_func, &a, NULL);
+  gpr_thd_new(&id, thd_func, &a, nullptr);
 
   grpc_slice_buffer_init(&outgoing);
   grpc_slice_buffer_add(&outgoing, slice);
@@ -152,14 +152,14 @@ void grpc_run_bad_client_test(
         GRPC_ERROR_CREATE_FROM_STATIC_STRING("Forced Disconnect"));
     grpc_endpoint_destroy(&exec_ctx, sfd.client);
     grpc_exec_ctx_finish(&exec_ctx);
-    sfd.client = NULL;
+    sfd.client = nullptr;
   }
 
   GPR_ASSERT(gpr_event_wait(&a.done_thd, grpc_timeout_seconds_to_deadline(5)));
 
-  if (sfd.client != NULL) {
+  if (sfd.client != nullptr) {
     // Validate client stream, if requested.
-    if (client_validator != NULL) {
+    if (client_validator != nullptr) {
       gpr_timespec deadline = grpc_timeout_seconds_to_deadline(5);
       grpc_slice_buffer incoming;
       grpc_slice_buffer_init(&incoming);
@@ -176,7 +176,7 @@ void grpc_run_bad_client_test(
         do {
           GPR_ASSERT(gpr_time_cmp(deadline, gpr_now(deadline.clock_type)) > 0);
           GPR_ASSERT(grpc_completion_queue_next(
-                         a.cq, grpc_timeout_milliseconds_to_deadline(100), NULL)
+                         a.cq, grpc_timeout_milliseconds_to_deadline(100), nullptr)
                          .type == GRPC_QUEUE_TIMEOUT);
         } while (!gpr_event_get(&read_done_event));
         if (client_validator(&incoming)) break;
@@ -196,10 +196,10 @@ void grpc_run_bad_client_test(
 
   GPR_ASSERT(
       gpr_event_wait(&a.done_write, grpc_timeout_seconds_to_deadline(1)));
-  shutdown_cq = grpc_completion_queue_create_for_pluck(NULL);
-  grpc_server_shutdown_and_notify(a.server, shutdown_cq, NULL);
+  shutdown_cq = grpc_completion_queue_create_for_pluck(nullptr);
+  grpc_server_shutdown_and_notify(a.server, shutdown_cq, nullptr);
   GPR_ASSERT(grpc_completion_queue_pluck(
-                 shutdown_cq, NULL, grpc_timeout_seconds_to_deadline(1), NULL)
+                 shutdown_cq, nullptr, grpc_timeout_seconds_to_deadline(1), nullptr)
                  .type == GRPC_OP_COMPLETE);
   grpc_completion_queue_destroy(shutdown_cq);
   grpc_server_destroy(a.server);
diff --git a/test/core/bad_client/tests/badreq.cc b/test/core/bad_client/tests/badreq.cc
index 5273c831e5..c30244e0cd 100644
--- a/test/core/bad_client/tests/badreq.cc
+++ b/test/core/bad_client/tests/badreq.cc
@@ -31,7 +31,7 @@ static void verifier(grpc_server* server, grpc_completion_queue* cq,
                      void* registered_method) {
   while (grpc_server_has_open_connections(server)) {
     GPR_ASSERT(grpc_completion_queue_next(
-                   cq, grpc_timeout_milliseconds_to_deadline(20), NULL)
+                   cq, grpc_timeout_milliseconds_to_deadline(20), nullptr)
                    .type == GRPC_QUEUE_TIMEOUT);
   }
 }
@@ -41,7 +41,7 @@ int main(int argc, char** argv) {
 
   /* invalid content type */
   GRPC_RUN_BAD_CLIENT_TEST(
-      verifier, NULL,
+      verifier, nullptr,
       PFX_STR
       "\x00\x00\xc2\x01\x04\x00\x00\x00\x01"
       "\x10\x05:path\x08/foo/bar"
@@ -57,7 +57,7 @@ int main(int argc, char** argv) {
 
   /* invalid te */
   GRPC_RUN_BAD_CLIENT_TEST(
-      verifier, NULL,
+      verifier, nullptr,
       PFX_STR
       "\x00\x00\xcb\x01\x04\x00\x00\x00\x01"
       "\x10\x05:path\x08/foo/bar"
@@ -75,7 +75,7 @@ int main(int argc, char** argv) {
 
   /* two path headers */
   GRPC_RUN_BAD_CLIENT_TEST(
-      verifier, NULL,
+      verifier, nullptr,
       PFX_STR
       "\x00\x00\xd9\x01\x04\x00\x00\x00\x01"
       "\x10\x05:path\x08/foo/bar"
@@ -93,7 +93,7 @@ int main(int argc, char** argv) {
 
   /* bad accept-encoding algorithm */
   GRPC_RUN_BAD_CLIENT_TEST(
-      verifier, NULL,
+      verifier, nullptr,
       PFX_STR
       "\x00\x00\xd2\x01\x04\x00\x00\x00\x01"
       "\x10\x05:path\x08/foo/bar"
@@ -110,7 +110,7 @@ int main(int argc, char** argv) {
 
   /* bad grpc-encoding algorithm */
   GRPC_RUN_BAD_CLIENT_TEST(
-      verifier, NULL,
+      verifier, nullptr,
       PFX_STR
       "\x00\x00\xf5\x01\x04\x00\x00\x00\x01"
       "\x10\x05:path\x08/foo/bar"
diff --git a/test/core/bad_client/tests/connection_prefix.cc b/test/core/bad_client/tests/connection_prefix.cc
index a4fd734e04..8ffc5a5be8 100644
--- a/test/core/bad_client/tests/connection_prefix.cc
+++ b/test/core/bad_client/tests/connection_prefix.cc
@@ -23,7 +23,7 @@ static void verifier(grpc_server* server, grpc_completion_queue* cq,
                      void* registered_method) {
   while (grpc_server_has_open_connections(server)) {
     GPR_ASSERT(grpc_completion_queue_next(
-                   cq, grpc_timeout_milliseconds_to_deadline(20), NULL)
+                   cq, grpc_timeout_milliseconds_to_deadline(20), nullptr)
                    .type == GRPC_QUEUE_TIMEOUT);
   }
 }
@@ -31,30 +31,30 @@ static void verifier(grpc_server* server, grpc_completion_queue* cq,
 int main(int argc, char** argv) {
   grpc_test_init(argc, argv);
 
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL, "X", 0);
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL, "PX", 0);
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL, "PRX", 0);
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL, "PRIX", 0);
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL, "PRI X", 0);
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL, "PRI *X", 0);
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL, "PRI * X", 0);
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL, "PRI * HX", 0);
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL, "PRI * HTX", 0);
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL, "PRI * HTTX", 0);
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL, "PRI * HTTPX", 0);
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL, "PRI * HTTP/X", 0);
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL, "PRI * HTTP/2X", 0);
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL, "PRI * HTTP/2.X", 0);
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL, "PRI * HTTP/2.0X", 0);
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL, "PRI * HTTP/2.0\rX", 0);
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL, "PRI * HTTP/2.0\r\nX", 0);
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL, "PRI * HTTP/2.0\r\n\rX", 0);
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL, "PRI * HTTP/2.0\r\n\r\nX", 0);
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL, "PRI * HTTP/2.0\r\n\r\nSX", 0);
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL, "PRI * HTTP/2.0\r\n\r\nSMX", 0);
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL, "PRI * HTTP/2.0\r\n\r\nSM\rX", 0);
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL, "PRI * HTTP/2.0\r\n\r\nSM\r\nX", 0);
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL, "PRI * HTTP/2.0\r\n\r\nSM\r\n\rX",
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr, "X", 0);
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr, "PX", 0);
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr, "PRX", 0);
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr, "PRIX", 0);
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr, "PRI X", 0);
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr, "PRI *X", 0);
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr, "PRI * X", 0);
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr, "PRI * HX", 0);
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr, "PRI * HTX", 0);
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr, "PRI * HTTX", 0);
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr, "PRI * HTTPX", 0);
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr, "PRI * HTTP/X", 0);
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr, "PRI * HTTP/2X", 0);
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr, "PRI * HTTP/2.X", 0);
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr, "PRI * HTTP/2.0X", 0);
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr, "PRI * HTTP/2.0\rX", 0);
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr, "PRI * HTTP/2.0\r\nX", 0);
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr, "PRI * HTTP/2.0\r\n\rX", 0);
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr, "PRI * HTTP/2.0\r\n\r\nX", 0);
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr, "PRI * HTTP/2.0\r\n\r\nSX", 0);
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr, "PRI * HTTP/2.0\r\n\r\nSMX", 0);
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr, "PRI * HTTP/2.0\r\n\r\nSM\rX", 0);
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr, "PRI * HTTP/2.0\r\n\r\nSM\r\nX", 0);
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr, "PRI * HTTP/2.0\r\n\r\nSM\r\n\rX",
                            0);
   return 0;
 }
diff --git a/test/core/bad_client/tests/head_of_line_blocking.cc b/test/core/bad_client/tests/head_of_line_blocking.cc
index aad335cf5b..bbc5611991 100644
--- a/test/core/bad_client/tests/head_of_line_blocking.cc
+++ b/test/core/bad_client/tests/head_of_line_blocking.cc
@@ -74,7 +74,7 @@ static void verifier(grpc_server* server, grpc_completion_queue* cq,
   cq_verifier* cqv = cq_verifier_create(cq);
   grpc_metadata_array request_metadata_recv;
   gpr_timespec deadline;
-  grpc_byte_buffer* payload = NULL;
+  grpc_byte_buffer* payload = nullptr;
 
   grpc_metadata_array_init(&request_metadata_recv);
 
@@ -85,7 +85,7 @@ static void verifier(grpc_server* server, grpc_completion_queue* cq,
   CQ_EXPECT_COMPLETION(cqv, tag(101), 1);
   cq_verify(cqv);
 
-  GPR_ASSERT(payload != NULL);
+  GPR_ASSERT(payload != nullptr);
 
   grpc_metadata_array_destroy(&request_metadata_recv);
   grpc_call_unref(s);
@@ -129,7 +129,7 @@ int main(int argc, char** argv) {
     addbuf(hdr, sizeof(hdr));
     addbuf(msg, FRAME_SIZE);
   }
-  grpc_run_bad_client_test(verifier, NULL, g_buffer, g_count, 0);
+  grpc_run_bad_client_test(verifier, nullptr, g_buffer, g_count, 0);
   gpr_free(g_buffer);
 
   return 0;
diff --git a/test/core/bad_client/tests/headers.cc b/test/core/bad_client/tests/headers.cc
index f96c6f0028..e0b77e043a 100644
--- a/test/core/bad_client/tests/headers.cc
+++ b/test/core/bad_client/tests/headers.cc
@@ -27,7 +27,7 @@ static void verifier(grpc_server* server, grpc_completion_queue* cq,
                      void* registered_method) {
   while (grpc_server_has_open_connections(server)) {
     GPR_ASSERT(grpc_completion_queue_next(
-                   cq, grpc_timeout_milliseconds_to_deadline(20), NULL)
+                   cq, grpc_timeout_milliseconds_to_deadline(20), nullptr)
                    .type == GRPC_QUEUE_TIMEOUT);
   }
 }
@@ -36,275 +36,275 @@ int main(int argc, char** argv) {
   grpc_test_init(argc, argv);
 
   /* partial http2 header prefixes */
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL, PFX_STR "\x00",
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr, PFX_STR "\x00",
                            GRPC_BAD_CLIENT_DISCONNECT);
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL, PFX_STR "\x00\x00",
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr, PFX_STR "\x00\x00",
                            GRPC_BAD_CLIENT_DISCONNECT);
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL, PFX_STR "\x00\x00\x00",
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr, PFX_STR "\x00\x00\x00",
                            GRPC_BAD_CLIENT_DISCONNECT);
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL, PFX_STR "\x00\x00\x00\x01",
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr, PFX_STR "\x00\x00\x00\x01",
                            GRPC_BAD_CLIENT_DISCONNECT);
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL, PFX_STR "\x00\x00\x00\x01\x00",
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr, PFX_STR "\x00\x00\x00\x01\x00",
                            GRPC_BAD_CLIENT_DISCONNECT);
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL, PFX_STR "\x00\x00\x00\x01\x04",
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr, PFX_STR "\x00\x00\x00\x01\x04",
                            GRPC_BAD_CLIENT_DISCONNECT);
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL, PFX_STR "\x00\x00\x00\x01\x05",
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr, PFX_STR "\x00\x00\x00\x01\x05",
                            GRPC_BAD_CLIENT_DISCONNECT);
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL, PFX_STR "\x00\x00\x00\x01\x04\x00",
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr, PFX_STR "\x00\x00\x00\x01\x04\x00",
                            GRPC_BAD_CLIENT_DISCONNECT);
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL,
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr,
                            PFX_STR "\x00\x00\x00\x01\x04\x00\x00",
                            GRPC_BAD_CLIENT_DISCONNECT);
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL,
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr,
                            PFX_STR "\x00\x00\x00\x01\x04\x00\x00\x00",
                            GRPC_BAD_CLIENT_DISCONNECT);
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL,
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr,
                            PFX_STR "\x00\x00\x00\x01\x04\x00\x00\x00\x00",
                            GRPC_BAD_CLIENT_DISCONNECT);
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL,
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr,
                            PFX_STR "\x00\x00\x00\x01\x04\x00\x00\x00\x01",
                            GRPC_BAD_CLIENT_DISCONNECT);
 
   /* test adding prioritization data */
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL,
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr,
                            PFX_STR
                            "\x00\x00\x01\x01\x24\x00\x00\x00\x01"
                            "\x00",
                            0);
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL,
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr,
                            PFX_STR
                            "\x00\x00\x02\x01\x24\x00\x00\x00\x01"
                            "\x00\x00",
                            0);
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL,
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr,
                            PFX_STR
                            "\x00\x00\x03\x01\x24\x00\x00\x00\x01"
                            "\x00\x00\x00",
                            0);
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL,
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr,
                            PFX_STR
                            "\x00\x00\x04\x01\x24\x00\x00\x00\x01"
                            "\x00\x00\x00\x00",
                            0);
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL,
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr,
                            PFX_STR
                            "\x00\x00\x05\x01\x24\x00\x00\x00\x01"
                            "",
                            GRPC_BAD_CLIENT_DISCONNECT);
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL,
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr,
                            PFX_STR
                            "\x00\x00\x05\x01\x24\x00\x00\x00\x01"
                            "\x00",
                            GRPC_BAD_CLIENT_DISCONNECT);
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL,
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr,
                            PFX_STR
                            "\x00\x00\x05\x01\x24\x00\x00\x00\x01"
                            "\x00\x00",
                            GRPC_BAD_CLIENT_DISCONNECT);
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL,
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr,
                            PFX_STR
                            "\x00\x00\x05\x01\x24\x00\x00\x00\x01"
                            "\x00\x00\x00",
                            GRPC_BAD_CLIENT_DISCONNECT);
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL,
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr,
                            PFX_STR
                            "\x00\x00\x05\x01\x24\x00\x00\x00\x01"
                            "\x00\x00\x00\x00",
                            GRPC_BAD_CLIENT_DISCONNECT);
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL,
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr,
                            PFX_STR
                            "\x00\x00\x05\x01\x24\x00\x00\x00\x01"
                            "\x00\x00\x00\x00\x00",
                            GRPC_BAD_CLIENT_DISCONNECT);
 
   /* test looking up an invalid index */
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL,
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr,
                            PFX_STR
                            "\x00\x00\x01\x01\x04\x00\x00\x00\x01"
                            "\xfe",
                            0);
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL,
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr,
                            PFX_STR
                            "\x00\x00\x04\x01\x04\x00\x00\x00\x01"
                            "\x7f\x7f\x01"
                            "a",
                            0);
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL,
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr,
                            PFX_STR
                            "\x00\x00\x04\x01\x04\x00\x00\x00\x01"
                            "\x0f\x7f\x01"
                            "a",
                            0);
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL,
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr,
                            PFX_STR
                            "\x00\x00\x04\x01\x04\x00\x00\x00\x01"
                            "\x1f\x7f\x01"
                            "a",
                            0);
   /* test nvr, not indexed in static table */
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL,
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr,
                            PFX_STR
                            "\x00\x00\x03\x01\x04\x00\x00\x00\x01"
                            "\x01\x01"
                            "a",
                            GRPC_BAD_CLIENT_DISCONNECT);
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL,
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr,
                            PFX_STR
                            "\x00\x00\x03\x01\x04\x00\x00\x00\x01"
                            "\x11\x01"
                            "a",
                            GRPC_BAD_CLIENT_DISCONNECT);
   /* illegal op code */
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL,
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr,
                            PFX_STR
                            "\x00\x00\x01\x01\x04\x00\x00\x00\x01"
                            "\x80",
                            0);
   /* parse some long indices */
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL,
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr,
                            PFX_STR
                            "\x00\x00\x02\x01\x04\x00\x00\x00\x01"
                            "\xff\x00",
                            0);
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL,
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr,
                            PFX_STR
                            "\x00\x00\x03\x01\x04\x00\x00\x00\x01"
                            "\xff\x80\x00",
                            0);
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL,
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr,
                            PFX_STR
                            "\x00\x00\x04\x01\x04\x00\x00\x00\x01"
                            "\xff\x80\x80\x00",
                            0);
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL,
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr,
                            PFX_STR
                            "\x00\x00\x05\x01\x04\x00\x00\x00\x01"
                            "\xff\x80\x80\x80\x00",
                            0);
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL,
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr,
                            PFX_STR
                            "\x00\x00\x06\x01\x04\x00\x00\x00\x01"
                            "\xff\x80\x80\x80\x80\x00",
                            0);
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL,
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr,
                            PFX_STR
                            "\x00\x00\x07\x01\x04\x00\x00\x00\x01"
                            "\xff\x80\x80\x80\x80\x80\x00",
                            0);
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL,
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr,
                            PFX_STR
                            "\x00\x00\x08\x01\x04\x00\x00\x00\x01"
                            "\xff",
                            GRPC_BAD_CLIENT_DISCONNECT);
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL,
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr,
                            PFX_STR
                            "\x00\x00\x08\x01\x04\x00\x00\x00\x01"
                            "\xff\x80",
                            GRPC_BAD_CLIENT_DISCONNECT);
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL,
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr,
                            PFX_STR
                            "\x00\x00\x08\x01\x04\x00\x00\x00\x01"
                            "\xff\x80\x80",
                            GRPC_BAD_CLIENT_DISCONNECT);
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL,
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr,
                            PFX_STR
                            "\x00\x00\x08\x01\x04\x00\x00\x00\x01"
                            "\xff\x80\x80\x80",
                            GRPC_BAD_CLIENT_DISCONNECT);
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL,
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr,
                            PFX_STR
                            "\x00\x00\x08\x01\x04\x00\x00\x00\x01"
                            "\xff\x80\x80\x80\x80",
                            GRPC_BAD_CLIENT_DISCONNECT);
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL,
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr,
                            PFX_STR
                            "\x00\x00\x08\x01\x04\x00\x00\x00\x01"
                            "\xff\x80\x80\x80\x80\x80",
                            GRPC_BAD_CLIENT_DISCONNECT);
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL,
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr,
                            PFX_STR
                            "\x00\x00\x08\x01\x04\x00\x00\x00\x01"
                            "\xff\x80\x80\x80\x80\x80\x80",
                            GRPC_BAD_CLIENT_DISCONNECT);
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL,
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr,
                            PFX_STR
                            "\x00\x00\x08\x01\x04\x00\x00\x00\x01"
                            "\xff\x80\x80\x80\x80\x80\x80\x00",
                            0);
   /* overflow on byte 4 */
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL,
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr,
                            PFX_STR
                            "\x00\x00\x06\x01\x04\x00\x00\x00\x01"
                            "\xff\x80\x80\x80\x80\x7f",
                            GRPC_BAD_CLIENT_DISCONNECT);
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL,
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr,
                            PFX_STR
                            "\x00\x00\x06\x01\x04\x00\x00\x00\x01"
                            "\xff\xff\xff\xff\xff\x0f",
                            GRPC_BAD_CLIENT_DISCONNECT);
   /* overflow after byte 4 */
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL,
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr,
                            PFX_STR
                            "\x00\x00\x08\x01\x04\x00\x00\x00\x01"
                            "\xff\x80\x80\x80\x80\x80\x80\x02",
                            0);
   /* end of headers mid-opcode */
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL,
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr,
                            PFX_STR
                            "\x00\x00\x01\x01\x04\x00\x00\x00\x01"
                            "\x01",
                            GRPC_BAD_CLIENT_DISCONNECT);
 
   /* dynamic table size update: set to default */
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL,
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr,
                            PFX_STR
                            "\x00\x00\x03\x01\x04\x00\x00\x00\x01"
                            "\x3f\xe1\x1f",
                            GRPC_BAD_CLIENT_DISCONNECT);
   /* dynamic table size update: set too large */
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL,
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr,
                            PFX_STR
                            "\x00\x00\x03\x01\x04\x00\x00\x00\x01"
                            "\x3f\xf1\x1f",
                            0);
   /* dynamic table size update: set twice */
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL,
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr,
                            PFX_STR
                            "\x00\x00\x04\x01\x04\x00\x00\x00\x01"
                            "\x20\x3f\xe1\x1f",
                            GRPC_BAD_CLIENT_DISCONNECT);
   /* dynamic table size update: set thrice */
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL,
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr,
                            PFX_STR
                            "\x00\x00\x03\x01\x04\x00\x00\x00\x01"
                            "\x20\x20\x20",
                            0);
 
   /* non-ending header followed by continuation frame */
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL,
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr,
                            PFX_STR
                            "\x00\x00\x00\x01\x00\x00\x00\x00\x01"
                            "\x00\x00\x00\x09\x04\x00\x00\x00\x01",
                            GRPC_BAD_CLIENT_DISCONNECT);
   /* non-ending header followed by non-continuation frame */
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL,
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr,
                            PFX_STR
                            "\x00\x00\x00\x01\x00\x00\x00\x00\x01"
                            "\x00\x00\x00\x00\x04\x00\x00\x00\x01",
                            0);
   /* non-ending header followed by a continuation frame for a different stream
    */
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL,
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr,
                            PFX_STR
                            "\x00\x00\x00\x01\x04\x00\x00\x00\x01"
                            "\x00\x00\x00\x01\x00\x00\x00\x00\x03"
                            "\x00\x00\x00\x09\x04\x00\x00\x00\x01",
                            0);
   /* opening with a continuation frame */
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL,
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr,
                            PFX_STR "\x00\x00\x00\x09\x04\x00\x00\x00\x01", 0);
   /* three header frames */
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL,
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr,
                            PFX_STR
                            "\x00\x00\x00\x01\x04\x00\x00\x00\x01"
                            "\x00\x00\x00\x01\x04\x00\x00\x00\x01"
@@ -312,19 +312,19 @@ int main(int argc, char** argv) {
                            GRPC_BAD_CLIENT_DISCONNECT);
 
   /* an invalid header found with fuzzing */
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL,
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr,
                            PFX_STR "\x00\x00\x00\x01\x39\x67\xed\x1d\x64",
                            GRPC_BAD_CLIENT_DISCONNECT);
 
   /* a badly encoded timeout value */
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL,
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr,
                            PFX_STR
                            "\x00\x00\x19\x01\x04\x00\x00\x00\x01"
                            "\x10\x0cgrpc-timeout\x0a"
                            "15 seconds",
                            GRPC_BAD_CLIENT_DISCONNECT);
   /* a badly encoded timeout value: twice (catches caching) */
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL,
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr,
                            PFX_STR
                            "\x00\x00\x19\x01\x04\x00\x00\x00\x01"
                            "\x10\x0cgrpc-timeout\x0a"
diff --git a/test/core/bad_client/tests/initial_settings_frame.cc b/test/core/bad_client/tests/initial_settings_frame.cc
index dde9d4b5d3..4a01c9ee3e 100644
--- a/test/core/bad_client/tests/initial_settings_frame.cc
+++ b/test/core/bad_client/tests/initial_settings_frame.cc
@@ -26,7 +26,7 @@ static void verifier(grpc_server* server, grpc_completion_queue* cq,
                      void* registered_method) {
   while (grpc_server_has_open_connections(server)) {
     GPR_ASSERT(grpc_completion_queue_next(
-                   cq, grpc_timeout_milliseconds_to_deadline(20), NULL)
+                   cq, grpc_timeout_milliseconds_to_deadline(20), nullptr)
                    .type == GRPC_QUEUE_TIMEOUT);
   }
 }
@@ -35,73 +35,73 @@ int main(int argc, char** argv) {
   grpc_test_init(argc, argv);
 
   /* various partial prefixes */
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL, PFX_STR "\x00",
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr, PFX_STR "\x00",
                            GRPC_BAD_CLIENT_DISCONNECT);
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL, PFX_STR "\x00\x00",
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr, PFX_STR "\x00\x00",
                            GRPC_BAD_CLIENT_DISCONNECT);
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL, PFX_STR "\x00\x00\x00",
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr, PFX_STR "\x00\x00\x00",
                            GRPC_BAD_CLIENT_DISCONNECT);
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL, PFX_STR "\x06",
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr, PFX_STR "\x06",
                            GRPC_BAD_CLIENT_DISCONNECT);
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL, PFX_STR "\x00\x06",
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr, PFX_STR "\x00\x06",
                            GRPC_BAD_CLIENT_DISCONNECT);
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL, PFX_STR "\x00\x00\x06",
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr, PFX_STR "\x00\x00\x06",
                            GRPC_BAD_CLIENT_DISCONNECT);
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL, PFX_STR "\x00\x00\x00\x04",
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr, PFX_STR "\x00\x00\x00\x04",
                            GRPC_BAD_CLIENT_DISCONNECT);
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL, PFX_STR "\x00\x00\x00\x04\x00",
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr, PFX_STR "\x00\x00\x00\x04\x00",
                            GRPC_BAD_CLIENT_DISCONNECT);
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL, PFX_STR "\x00\x00\x00\x04\x01",
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr, PFX_STR "\x00\x00\x00\x04\x01",
                            GRPC_BAD_CLIENT_DISCONNECT);
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL, PFX_STR "\x00\x00\x00\x04\xff",
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr, PFX_STR "\x00\x00\x00\x04\xff",
                            GRPC_BAD_CLIENT_DISCONNECT);
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL, PFX_STR "\x00\x00\x00\x04\x00\x00",
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr, PFX_STR "\x00\x00\x00\x04\x00\x00",
                            GRPC_BAD_CLIENT_DISCONNECT);
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL,
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr,
                            PFX_STR "\x00\x00\x00\x04\x00\x00\x00",
                            GRPC_BAD_CLIENT_DISCONNECT);
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL,
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr,
                            PFX_STR "\x00\x00\x00\x04\x00\x00\x00\x00",
                            GRPC_BAD_CLIENT_DISCONNECT);
   /* must not send frames with stream id != 0 */
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL,
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr,
                            PFX_STR "\x00\x00\x00\x04\x00\x00\x00\x00\x01", 0);
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL,
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr,
                            PFX_STR "\x00\x00\x00\x04\x00\x40\x00\x00\x00", 0);
   /* settings frame must be a multiple of six bytes long */
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL,
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr,
                            PFX_STR "\x00\x00\x01\x04\x00\x00\x00\x00\x00", 0);
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL,
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr,
                            PFX_STR "\x00\x00\x02\x04\x00\x00\x00\x00\x00", 0);
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL,
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr,
                            PFX_STR "\x00\x00\x03\x04\x00\x00\x00\x00\x00", 0);
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL,
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr,
                            PFX_STR "\x00\x00\x04\x04\x00\x00\x00\x00\x00", 0);
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL,
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr,
                            PFX_STR "\x00\x00\x05\x04\x00\x00\x00\x00\x00", 0);
   /* some settings values are illegal */
   /* max frame size = 0 */
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL,
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr,
                            PFX_STR ONE_SETTING_HDR "\x00\x05\x00\x00\x00\x00",
                            GRPC_BAD_CLIENT_DISCONNECT);
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL,
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr,
                            PFX_STR ONE_SETTING_HDR "\x00\x06\xff\xff\xff\xff",
                            GRPC_BAD_CLIENT_DISCONNECT);
   /* update intiial window size */
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL,
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr,
                            PFX_STR ONE_SETTING_HDR "\x00\x04\x00\x01\x00\x00",
                            GRPC_BAD_CLIENT_DISCONNECT);
   /* ack with data */
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL,
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr,
                            PFX_STR
                            "\x00\x00\x00\x04\x00\x00\x00\x00\x00"
                            "\x00\x00\x01\x04\x01\x00\x00\x00\x00",
                            0);
   /* settings frame with invalid flags */
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL,
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr,
                            PFX_STR "\x00\x00\x00\x04\x10\x00\x00\x00\x00", 0);
   /* unknown settings should be ignored */
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL,
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr,
                            PFX_STR ONE_SETTING_HDR "\x00\x99\x00\x00\x00\x00",
                            GRPC_BAD_CLIENT_DISCONNECT);
 
diff --git a/test/core/bad_client/tests/large_metadata.cc b/test/core/bad_client/tests/large_metadata.cc
index df7dd8f4b3..1ce0f28967 100644
--- a/test/core/bad_client/tests/large_metadata.cc
+++ b/test/core/bad_client/tests/large_metadata.cc
@@ -154,8 +154,8 @@ static void server_verifier_sends_too_much_metadata(grpc_server* server,
   op.data.send_initial_metadata.count = 1;
   op.data.send_initial_metadata.metadata = &meta;
   op.flags = 0;
-  op.reserved = NULL;
-  error = grpc_call_start_batch(s, &op, 1, tag(102), NULL);
+  op.reserved = nullptr;
+  error = grpc_call_start_batch(s, &op, 1, tag(102), nullptr);
   GPR_ASSERT(GRPC_CALL_OK == error);
   CQ_EXPECT_COMPLETION(cqv, tag(102), 0);  // Operation fails.
   cq_verify(cqv);
diff --git a/test/core/bad_client/tests/server_registered_method.cc b/test/core/bad_client/tests/server_registered_method.cc
index b1b11235de..6613c94b41 100644
--- a/test/core/bad_client/tests/server_registered_method.cc
+++ b/test/core/bad_client/tests/server_registered_method.cc
@@ -47,7 +47,7 @@ static void verifier_succeeds(grpc_server* server, grpc_completion_queue* cq,
   cq_verifier* cqv = cq_verifier_create(cq);
   grpc_metadata_array request_metadata_recv;
   gpr_timespec deadline;
-  grpc_byte_buffer* payload = NULL;
+  grpc_byte_buffer* payload = nullptr;
 
   grpc_metadata_array_init(&request_metadata_recv);
 
@@ -58,7 +58,7 @@ static void verifier_succeeds(grpc_server* server, grpc_completion_queue* cq,
   CQ_EXPECT_COMPLETION(cqv, tag(101), 1);
   cq_verify(cqv);
 
-  GPR_ASSERT(payload != NULL);
+  GPR_ASSERT(payload != nullptr);
 
   grpc_metadata_array_destroy(&request_metadata_recv);
   grpc_call_unref(s);
@@ -70,7 +70,7 @@ static void verifier_fails(grpc_server* server, grpc_completion_queue* cq,
                            void* registered_method) {
   while (grpc_server_has_open_connections(server)) {
     GPR_ASSERT(grpc_completion_queue_next(
-                   cq, grpc_timeout_milliseconds_to_deadline(20), NULL)
+                   cq, grpc_timeout_milliseconds_to_deadline(20), nullptr)
                    .type == GRPC_QUEUE_TIMEOUT);
   }
 }
@@ -80,45 +80,45 @@ int main(int argc, char** argv) {
 
   /* body generated with
    * tools/codegen/core/gen_server_registered_method_bad_client_test_body.py */
-  GRPC_RUN_BAD_CLIENT_TEST(verifier_fails, NULL,
+  GRPC_RUN_BAD_CLIENT_TEST(verifier_fails, nullptr,
                            PFX_STR "\x00\x00\x00\x00\x00\x00\x00\x00\x01",
                            GRPC_BAD_CLIENT_DISCONNECT);
-  GRPC_RUN_BAD_CLIENT_TEST(verifier_fails, NULL,
+  GRPC_RUN_BAD_CLIENT_TEST(verifier_fails, nullptr,
                            PFX_STR "\x00\x00\x01\x00\x00\x00\x00\x00\x01\x00",
                            GRPC_BAD_CLIENT_DISCONNECT);
-  GRPC_RUN_BAD_CLIENT_TEST(verifier_fails, NULL,
+  GRPC_RUN_BAD_CLIENT_TEST(verifier_fails, nullptr,
                            PFX_STR
                            "\x00\x00\x02\x00\x00\x00\x00\x00\x01\x00\x00",
                            GRPC_BAD_CLIENT_DISCONNECT);
-  GRPC_RUN_BAD_CLIENT_TEST(verifier_fails, NULL,
+  GRPC_RUN_BAD_CLIENT_TEST(verifier_fails, nullptr,
                            PFX_STR
                            "\x00\x00\x03\x00\x00\x00\x00\x00\x01\x00\x00\x00",
                            GRPC_BAD_CLIENT_DISCONNECT);
   GRPC_RUN_BAD_CLIENT_TEST(
-      verifier_fails, NULL,
+      verifier_fails, nullptr,
       PFX_STR "\x00\x00\x04\x00\x00\x00\x00\x00\x01\x00\x00\x00\x00",
       GRPC_BAD_CLIENT_DISCONNECT);
   GRPC_RUN_BAD_CLIENT_TEST(
-      verifier_succeeds, NULL,
+      verifier_succeeds, nullptr,
       PFX_STR "\x00\x00\x05\x00\x01\x00\x00\x00\x01\x00\x00\x00\x00\x00", 0);
   GRPC_RUN_BAD_CLIENT_TEST(
-      verifier_fails, NULL,
+      verifier_fails, nullptr,
       PFX_STR "\x00\x00\x05\x00\x00\x00\x00\x00\x01\x00\x00\x00\x00\x01",
       GRPC_BAD_CLIENT_DISCONNECT);
   GRPC_RUN_BAD_CLIENT_TEST(
-      verifier_succeeds, NULL,
+      verifier_succeeds, nullptr,
       PFX_STR "\x00\x00\x06\x00\x01\x00\x00\x00\x01\x00\x00\x00\x00\x01\x00",
       0);
   GRPC_RUN_BAD_CLIENT_TEST(
-      verifier_fails, NULL,
+      verifier_fails, nullptr,
       PFX_STR "\x00\x00\x05\x00\x00\x00\x00\x00\x01\x00\x00\x00\x00\x02",
       GRPC_BAD_CLIENT_DISCONNECT);
   GRPC_RUN_BAD_CLIENT_TEST(
-      verifier_fails, NULL,
+      verifier_fails, nullptr,
       PFX_STR "\x00\x00\x06\x00\x00\x00\x00\x00\x01\x00\x00\x00\x00\x02\x00",
       GRPC_BAD_CLIENT_DISCONNECT);
   GRPC_RUN_BAD_CLIENT_TEST(
-      verifier_succeeds, NULL,
+      verifier_succeeds, nullptr,
       PFX_STR
       "\x00\x00\x07\x00\x01\x00\x00\x00\x01\x00\x00\x00\x00\x02\x00\x00",
       0);
diff --git a/test/core/bad_client/tests/simple_request.cc b/test/core/bad_client/tests/simple_request.cc
index b9cc1e3259..9f4a03e69b 100644
--- a/test/core/bad_client/tests/simple_request.cc
+++ b/test/core/bad_client/tests/simple_request.cc
@@ -115,7 +115,7 @@ static void failure_verifier(grpc_server* server, grpc_completion_queue* cq,
                              void* registered_method) {
   while (grpc_server_has_open_connections(server)) {
     GPR_ASSERT(grpc_completion_queue_next(
-                   cq, grpc_timeout_milliseconds_to_deadline(20), NULL)
+                   cq, grpc_timeout_milliseconds_to_deadline(20), nullptr)
                    .type == GRPC_QUEUE_TIMEOUT);
   }
 }
@@ -124,44 +124,44 @@ int main(int argc, char** argv) {
   grpc_test_init(argc, argv);
 
   /* basic request: check that things are working */
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL, PFX_STR, 0);
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL, PFX_STR_UNUSUAL, 0);
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL, PFX_STR_UNUSUAL2, 0);
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr, PFX_STR, 0);
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr, PFX_STR_UNUSUAL, 0);
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr, PFX_STR_UNUSUAL2, 0);
 
   /* push an illegal data frame */
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL,
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr,
                            PFX_STR
                            "\x00\x00\x05\x00\x00\x00\x00\x00\x01"
                            "\x34\x00\x00\x00\x00",
                            0);
 
   /* push a data frame with bad flags */
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL,
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr,
                            PFX_STR "\x00\x00\x00\x00\x02\x00\x00\x00\x01", 0);
   /* push a window update with a bad length */
-  GRPC_RUN_BAD_CLIENT_TEST(failure_verifier, NULL,
+  GRPC_RUN_BAD_CLIENT_TEST(failure_verifier, nullptr,
                            PFX_STR "\x00\x00\x01\x08\x00\x00\x00\x00\x01", 0);
   /* push a window update with bad flags */
-  GRPC_RUN_BAD_CLIENT_TEST(failure_verifier, NULL,
+  GRPC_RUN_BAD_CLIENT_TEST(failure_verifier, nullptr,
                            PFX_STR "\x00\x00\x00\x08\x10\x00\x00\x00\x01", 0);
   /* push a window update with bad data */
-  GRPC_RUN_BAD_CLIENT_TEST(failure_verifier, NULL,
+  GRPC_RUN_BAD_CLIENT_TEST(failure_verifier, nullptr,
                            PFX_STR
                            "\x00\x00\x04\x08\x00\x00\x00\x00\x01"
                            "\xff\xff\xff\xff",
                            0);
   /* push a short goaway */
-  GRPC_RUN_BAD_CLIENT_TEST(failure_verifier, NULL,
+  GRPC_RUN_BAD_CLIENT_TEST(failure_verifier, nullptr,
                            PFX_STR "\x00\x00\x04\x07\x00\x00\x00\x00\x00", 0);
   /* disconnect before sending goaway */
-  GRPC_RUN_BAD_CLIENT_TEST(failure_verifier, NULL,
+  GRPC_RUN_BAD_CLIENT_TEST(failure_verifier, nullptr,
                            PFX_STR "\x00\x01\x12\x07\x00\x00\x00\x00\x00",
                            GRPC_BAD_CLIENT_DISCONNECT);
   /* push a rst_stream with a bad length */
-  GRPC_RUN_BAD_CLIENT_TEST(failure_verifier, NULL,
+  GRPC_RUN_BAD_CLIENT_TEST(failure_verifier, nullptr,
                            PFX_STR "\x00\x00\x01\x03\x00\x00\x00\x00\x01", 0);
   /* push a rst_stream with bad flags */
-  GRPC_RUN_BAD_CLIENT_TEST(failure_verifier, NULL,
+  GRPC_RUN_BAD_CLIENT_TEST(failure_verifier, nullptr,
                            PFX_STR "\x00\x00\x00\x03\x10\x00\x00\x00\x01", 0);
 
   return 0;
diff --git a/test/core/bad_client/tests/unknown_frame.cc b/test/core/bad_client/tests/unknown_frame.cc
index b8367a2b65..d962a4244d 100644
--- a/test/core/bad_client/tests/unknown_frame.cc
+++ b/test/core/bad_client/tests/unknown_frame.cc
@@ -27,7 +27,7 @@ static void verifier(grpc_server* server, grpc_completion_queue* cq,
                      void* registered_method) {
   while (grpc_server_has_open_connections(server)) {
     GPR_ASSERT(grpc_completion_queue_next(
-                   cq, grpc_timeout_milliseconds_to_deadline(20), NULL)
+                   cq, grpc_timeout_milliseconds_to_deadline(20), nullptr)
                    .type == GRPC_QUEUE_TIMEOUT);
   }
 }
@@ -36,7 +36,7 @@ int main(int argc, char** argv) {
   grpc_test_init(argc, argv);
 
   /* test adding prioritization data */
-  GRPC_RUN_BAD_CLIENT_TEST(verifier, NULL,
+  GRPC_RUN_BAD_CLIENT_TEST(verifier, nullptr,
                            PFX_STR "\x00\x00\x00\x88\x00\x00\x00\x00\x01",
                            GRPC_BAD_CLIENT_DISCONNECT);
 
diff --git a/test/core/bad_client/tests/window_overflow.cc b/test/core/bad_client/tests/window_overflow.cc
index cb4b790de2..f4bd81828b 100644
--- a/test/core/bad_client/tests/window_overflow.cc
+++ b/test/core/bad_client/tests/window_overflow.cc
@@ -46,7 +46,7 @@ static void verifier(grpc_server* server, grpc_completion_queue* cq,
                      void* registered_method) {
   while (grpc_server_has_open_connections(server)) {
     GPR_ASSERT(grpc_completion_queue_next(
-                   cq, grpc_timeout_milliseconds_to_deadline(20), NULL)
+                   cq, grpc_timeout_milliseconds_to_deadline(20), nullptr)
                    .type == GRPC_QUEUE_TIMEOUT);
   }
 }
@@ -90,7 +90,7 @@ int main(int argc, char** argv) {
       addbuf(message, sizeof(message));
     }
   }
-  grpc_run_bad_client_test(verifier, NULL, g_buffer, g_count,
+  grpc_run_bad_client_test(verifier, nullptr, g_buffer, g_count,
                            GRPC_BAD_CLIENT_LARGE_REQUEST);
   gpr_free(g_buffer);