Merge pull request #9252 from ctiller/write_buffering

Fix write buffering, add tests

6 files changed, 607 insertions, 0 deletions

diff --git a/test/core/end2end/end2end_nosec_tests.c b/test/core/end2end/end2end_nosec_tests.c
index 663489082f..b162bf2f40 100644
--- a/test/core/end2end/end2end_nosec_tests.c
+++ b/test/core/end2end/end2end_nosec_tests.c
@@ -135,6 +135,10 @@ extern void streaming_error_response(grpc_end2end_test_config config);
 extern void streaming_error_response_pre_init(void);
 extern void trailing_metadata(grpc_end2end_test_config config);
 extern void trailing_metadata_pre_init(void);
+extern void write_buffering(grpc_end2end_test_config config);
+extern void write_buffering_pre_init(void);
+extern void write_buffering_at_end(grpc_end2end_test_config config);
+extern void write_buffering_at_end_pre_init(void);
 
 void grpc_end2end_tests_pre_init(void) {
   GPR_ASSERT(!g_pre_init_called);
@@ -185,6 +189,8 @@ void grpc_end2end_tests_pre_init(void) {
   simple_request_pre_init();
   streaming_error_response_pre_init();
   trailing_metadata_pre_init();
+  write_buffering_pre_init();
+  write_buffering_at_end_pre_init();
 }
 
 void grpc_end2end_tests(int argc, char **argv,
@@ -240,6 +246,8 @@ void grpc_end2end_tests(int argc, char **argv,
     simple_request(config);
     streaming_error_response(config);
     trailing_metadata(config);
+    write_buffering(config);
+    write_buffering_at_end(config);
     return;
   }
 
@@ -428,6 +436,14 @@ void grpc_end2end_tests(int argc, char **argv,
       trailing_metadata(config);
       continue;
     }
+    if (0 == strcmp("write_buffering", argv[i])) {
+      write_buffering(config);
+      continue;
+    }
+    if (0 == strcmp("write_buffering_at_end", argv[i])) {
+      write_buffering_at_end(config);
+      continue;
+    }
     gpr_log(GPR_DEBUG, "not a test: '%s'", argv[i]);
     abort();
   }
diff --git a/test/core/end2end/end2end_tests.c b/test/core/end2end/end2end_tests.c
index 25c7c62fde..9bca0c81f6 100644
--- a/test/core/end2end/end2end_tests.c
+++ b/test/core/end2end/end2end_tests.c
@@ -137,6 +137,10 @@ extern void streaming_error_response(grpc_end2end_test_config config);
 extern void streaming_error_response_pre_init(void);
 extern void trailing_metadata(grpc_end2end_test_config config);
 extern void trailing_metadata_pre_init(void);
+extern void write_buffering(grpc_end2end_test_config config);
+extern void write_buffering_pre_init(void);
+extern void write_buffering_at_end(grpc_end2end_test_config config);
+extern void write_buffering_at_end_pre_init(void);
 
 void grpc_end2end_tests_pre_init(void) {
   GPR_ASSERT(!g_pre_init_called);
@@ -188,6 +192,8 @@ void grpc_end2end_tests_pre_init(void) {
   simple_request_pre_init();
   streaming_error_response_pre_init();
   trailing_metadata_pre_init();
+  write_buffering_pre_init();
+  write_buffering_at_end_pre_init();
 }
 
 void grpc_end2end_tests(int argc, char **argv,
@@ -244,6 +250,8 @@ void grpc_end2end_tests(int argc, char **argv,
     simple_request(config);
     streaming_error_response(config);
     trailing_metadata(config);
+    write_buffering(config);
+    write_buffering_at_end(config);
     return;
   }
 
@@ -436,6 +444,14 @@ void grpc_end2end_tests(int argc, char **argv,
       trailing_metadata(config);
       continue;
     }
+    if (0 == strcmp("write_buffering", argv[i])) {
+      write_buffering(config);
+      continue;
+    }
+    if (0 == strcmp("write_buffering_at_end", argv[i])) {
+      write_buffering_at_end(config);
+      continue;
+    }
     gpr_log(GPR_DEBUG, "not a test: '%s'", argv[i]);
     abort();
   }
diff --git a/test/core/end2end/gen_build_yaml.py b/test/core/end2end/gen_build_yaml.py
index 201a92a1fd..bcb7136eaa 100755
--- a/test/core/end2end/gen_build_yaml.py
+++ b/test/core/end2end/gen_build_yaml.py
@@ -143,6 +143,8 @@ END2END_TESTS = {
     'streaming_error_response': default_test_options,
     'trailing_metadata': default_test_options,
     'authority_not_supported': default_test_options,
+    'write_buffering': default_test_options,
+    'write_buffering_at_end': default_test_options,
 }
 
 
diff --git a/test/core/end2end/generate_tests.bzl b/test/core/end2end/generate_tests.bzl
index ed1ba3eea9..95c06de73f 100755
--- a/test/core/end2end/generate_tests.bzl
+++ b/test/core/end2end/generate_tests.bzl
@@ -131,6 +131,8 @@ END2END_TESTS = {
     'trailing_metadata': test_options(),
     'authority_not_supported': test_options(),
     'filter_latency': test_options(),
+    'write_buffering': test_options(),
+    'write_buffering_at_end': test_options(),
 }
 
 
diff --git a/test/core/end2end/tests/write_buffering.c b/test/core/end2end/tests/write_buffering.c
new file mode 100644
index 0000000000..856e9f0306
--- /dev/null
+++ b/test/core/end2end/tests/write_buffering.c
@@ -0,0 +1,291 @@
+/*
+ *
+ * Copyright 2017, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#include "test/core/end2end/end2end_tests.h"
+
+#include <stdio.h>
+#include <string.h>
+
+#include <grpc/byte_buffer.h>
+#include <grpc/support/alloc.h>
+#include <grpc/support/log.h>
+#include <grpc/support/time.h>
+#include <grpc/support/useful.h>
+#include "test/core/end2end/cq_verifier.h"
+
+static void *tag(intptr_t t) { return (void *)t; }
+
+static grpc_end2end_test_fixture begin_test(grpc_end2end_test_config config,
+                                            const char *test_name,
+                                            grpc_channel_args *client_args,
+                                            grpc_channel_args *server_args) {
+  grpc_end2end_test_fixture f;
+  gpr_log(GPR_INFO, "%s/%s", test_name, config.name);
+  f = config.create_fixture(client_args, server_args);
+  config.init_server(&f, server_args);
+  config.init_client(&f, client_args);
+  return f;
+}
+
+static gpr_timespec n_seconds_time(int n) {
+  return GRPC_TIMEOUT_SECONDS_TO_DEADLINE(n);
+}
+
+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);
+  } while (ev.type != GRPC_QUEUE_SHUTDOWN);
+}
+
+static void shutdown_server(grpc_end2end_test_fixture *f) {
+  if (!f->server) return;
+  grpc_server_shutdown_and_notify(f->server, f->cq, tag(1000));
+  GPR_ASSERT(grpc_completion_queue_pluck(
+                 f->cq, tag(1000), GRPC_TIMEOUT_SECONDS_TO_DEADLINE(5), NULL)
+                 .type == GRPC_OP_COMPLETE);
+  grpc_server_destroy(f->server);
+  f->server = NULL;
+}
+
+static void shutdown_client(grpc_end2end_test_fixture *f) {
+  if (!f->client) return;
+  grpc_channel_destroy(f->client);
+  f->client = NULL;
+}
+
+static void end_test(grpc_end2end_test_fixture *f) {
+  shutdown_server(f);
+  shutdown_client(f);
+
+  grpc_completion_queue_shutdown(f->cq);
+  drain_cq(f->cq);
+  grpc_completion_queue_destroy(f->cq);
+}
+
+/* Client sends a request with payload, server reads then returns status. */
+static void test_invoke_request_with_payload(grpc_end2end_test_config config) {
+  grpc_call *c;
+  grpc_call *s;
+  grpc_slice request_payload_slice1 =
+      grpc_slice_from_copied_string("hello world");
+  grpc_byte_buffer *request_payload1 =
+      grpc_raw_byte_buffer_create(&request_payload_slice1, 1);
+  grpc_slice request_payload_slice2 = grpc_slice_from_copied_string("abc123");
+  grpc_byte_buffer *request_payload2 =
+      grpc_raw_byte_buffer_create(&request_payload_slice2, 1);
+  gpr_timespec deadline = five_seconds_time();
+  grpc_end2end_test_fixture f =
+      begin_test(config, "test_invoke_request_with_payload", NULL, NULL);
+  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_call_details call_details;
+  grpc_status_code status;
+  grpc_call_error error;
+  char *details = NULL;
+  size_t details_capacity = 0;
+  int was_cancelled = 2;
+
+  c = grpc_channel_create_call(
+      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq, "/foo",
+      get_host_override_string("foo.test.google.fr:1234", config), deadline,
+      NULL);
+  GPR_ASSERT(c);
+
+  grpc_metadata_array_init(&initial_metadata_recv);
+  grpc_metadata_array_init(&trailing_metadata_recv);
+  grpc_metadata_array_init(&request_metadata_recv);
+  grpc_call_details_init(&call_details);
+
+  memset(ops, 0, sizeof(ops));
+  op = ops;
+  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);
+  GPR_ASSERT(GRPC_CALL_OK == error);
+
+  memset(ops, 0, sizeof(ops));
+  op = ops;
+  op->op = GRPC_OP_RECV_INITIAL_METADATA;
+  op->data.recv_initial_metadata = &initial_metadata_recv;
+  op->flags = 0;
+  op->reserved = NULL;
+  op++;
+  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(2), NULL);
+  GPR_ASSERT(GRPC_CALL_OK == error);
+
+  GPR_ASSERT(GRPC_CALL_OK == grpc_server_request_call(
+                                 f.server, &s, &call_details,
+                                 &request_metadata_recv, f.cq, f.cq, tag(101)));
+  CQ_EXPECT_COMPLETION(cqv, tag(1), true); /* send message is buffered */
+  CQ_EXPECT_COMPLETION(cqv, tag(101), true);
+  cq_verify(cqv);
+
+  memset(ops, 0, sizeof(ops));
+  op = ops;
+  op->op = GRPC_OP_SEND_MESSAGE;
+  op->data.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);
+  GPR_ASSERT(GRPC_CALL_OK == error);
+
+  memset(ops, 0, sizeof(ops));
+  op = ops;
+  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);
+  GPR_ASSERT(GRPC_CALL_OK == error);
+
+  /* recv message should not succeed yet - it's buffered at the client still */
+  memset(ops, 0, sizeof(ops));
+  op = ops;
+  op->op = GRPC_OP_RECV_MESSAGE;
+  op->data.recv_message = &request_payload_recv1;
+  op++;
+  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(103), NULL);
+  GPR_ASSERT(GRPC_CALL_OK == error);
+
+  CQ_EXPECT_COMPLETION(cqv, tag(2), true);
+  CQ_EXPECT_COMPLETION(cqv, tag(3), true);
+  CQ_EXPECT_COMPLETION(cqv, tag(102), true);
+  cq_verify(cqv);
+
+  /* send another message, this time not buffered */
+  memset(ops, 0, sizeof(ops));
+  op = ops;
+  op->op = GRPC_OP_SEND_MESSAGE;
+  op->data.send_message = request_payload2;
+  op->flags = 0;
+  op++;
+  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(4), NULL);
+  GPR_ASSERT(GRPC_CALL_OK == error);
+
+  /* now the first send should match up with the first recv */
+  CQ_EXPECT_COMPLETION(cqv, tag(103), true);
+  CQ_EXPECT_COMPLETION(cqv, tag(4), true);
+  cq_verify(cqv);
+
+  /* and the next recv should be ready immediately also */
+  memset(ops, 0, sizeof(ops));
+  op = ops;
+  op->op = GRPC_OP_RECV_MESSAGE;
+  op->data.recv_message = &request_payload_recv2;
+  op++;
+  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(104), NULL);
+  GPR_ASSERT(GRPC_CALL_OK == error);
+
+  CQ_EXPECT_COMPLETION(cqv, tag(104), true);
+  cq_verify(cqv);
+
+  memset(ops, 0, sizeof(ops));
+  op = ops;
+  op->op = GRPC_OP_SEND_CLOSE_FROM_CLIENT;
+  op->flags = 0;
+  op->reserved = NULL;
+  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->data.recv_status_on_client.status_details_capacity = &details_capacity;
+  op->flags = 0;
+  op->reserved = NULL;
+  op++;
+  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(4), NULL);
+
+  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++;
+  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_OK;
+  op->data.send_status_from_server.status_details = "xyz";
+  op->flags = 0;
+  op->reserved = NULL;
+  op++;
+  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(105), NULL);
+  GPR_ASSERT(GRPC_CALL_OK == error);
+
+  CQ_EXPECT_COMPLETION(cqv, tag(105), 1);
+  CQ_EXPECT_COMPLETION(cqv, tag(4), 1);
+  cq_verify(cqv);
+
+  GPR_ASSERT(status == GRPC_STATUS_OK);
+  GPR_ASSERT(0 == strcmp(details, "xyz"));
+  GPR_ASSERT(0 == strcmp(call_details.method, "/foo"));
+  validate_host_override_string("foo.test.google.fr:1234", call_details.host,
+                                config);
+  GPR_ASSERT(was_cancelled == 0);
+  GPR_ASSERT(byte_buffer_eq_string(request_payload_recv1, "hello world"));
+  GPR_ASSERT(byte_buffer_eq_string(request_payload_recv2, "abc123"));
+
+  gpr_free(details);
+  grpc_metadata_array_destroy(&initial_metadata_recv);
+  grpc_metadata_array_destroy(&trailing_metadata_recv);
+  grpc_metadata_array_destroy(&request_metadata_recv);
+  grpc_call_details_destroy(&call_details);
+
+  grpc_call_destroy(c);
+  grpc_call_destroy(s);
+
+  cq_verifier_destroy(cqv);
+
+  grpc_byte_buffer_destroy(request_payload1);
+  grpc_byte_buffer_destroy(request_payload_recv1);
+  grpc_byte_buffer_destroy(request_payload2);
+  grpc_byte_buffer_destroy(request_payload_recv2);
+
+  end_test(&f);
+  config.tear_down_data(&f);
+}
+
+void write_buffering(grpc_end2end_test_config config) {
+  test_invoke_request_with_payload(config);
+}
+
+void write_buffering_pre_init(void) {}
diff --git a/test/core/end2end/tests/write_buffering_at_end.c b/test/core/end2end/tests/write_buffering_at_end.c
new file mode 100644
index 0000000000..43aefcbdbc
--- /dev/null
+++ b/test/core/end2end/tests/write_buffering_at_end.c
@@ -0,0 +1,280 @@
+/*
+ *
+ * Copyright 2017, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#include "test/core/end2end/end2end_tests.h"
+
+#include <stdio.h>
+#include <string.h>
+
+#include <grpc/byte_buffer.h>
+#include <grpc/support/alloc.h>
+#include <grpc/support/log.h>
+#include <grpc/support/time.h>
+#include <grpc/support/useful.h>
+#include "test/core/end2end/cq_verifier.h"
+
+static void *tag(intptr_t t) { return (void *)t; }
+
+static grpc_end2end_test_fixture begin_test(grpc_end2end_test_config config,
+                                            const char *test_name,
+                                            grpc_channel_args *client_args,
+                                            grpc_channel_args *server_args) {
+  grpc_end2end_test_fixture f;
+  gpr_log(GPR_INFO, "%s/%s", test_name, config.name);
+  f = config.create_fixture(client_args, server_args);
+  config.init_server(&f, server_args);
+  config.init_client(&f, client_args);
+  return f;
+}
+
+static gpr_timespec n_seconds_time(int n) {
+  return GRPC_TIMEOUT_SECONDS_TO_DEADLINE(n);
+}
+
+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);
+  } while (ev.type != GRPC_QUEUE_SHUTDOWN);
+}
+
+static void shutdown_server(grpc_end2end_test_fixture *f) {
+  if (!f->server) return;
+  grpc_server_shutdown_and_notify(f->server, f->cq, tag(1000));
+  GPR_ASSERT(grpc_completion_queue_pluck(
+                 f->cq, tag(1000), GRPC_TIMEOUT_SECONDS_TO_DEADLINE(5), NULL)
+                 .type == GRPC_OP_COMPLETE);
+  grpc_server_destroy(f->server);
+  f->server = NULL;
+}
+
+static void shutdown_client(grpc_end2end_test_fixture *f) {
+  if (!f->client) return;
+  grpc_channel_destroy(f->client);
+  f->client = NULL;
+}
+
+static void end_test(grpc_end2end_test_fixture *f) {
+  shutdown_server(f);
+  shutdown_client(f);
+
+  grpc_completion_queue_shutdown(f->cq);
+  drain_cq(f->cq);
+  grpc_completion_queue_destroy(f->cq);
+}
+
+/* Client sends a request with payload, server reads then returns status. */
+static void test_invoke_request_with_payload(grpc_end2end_test_config config) {
+  grpc_call *c;
+  grpc_call *s;
+  grpc_slice request_payload_slice =
+      grpc_slice_from_copied_string("hello world");
+  grpc_byte_buffer *request_payload =
+      grpc_raw_byte_buffer_create(&request_payload_slice, 1);
+  gpr_timespec deadline = five_seconds_time();
+  grpc_end2end_test_fixture f =
+      begin_test(config, "test_invoke_request_with_payload", NULL, NULL);
+  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_call_details call_details;
+  grpc_status_code status;
+  grpc_call_error error;
+  char *details = NULL;
+  size_t details_capacity = 0;
+  int was_cancelled = 2;
+
+  c = grpc_channel_create_call(
+      f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq, "/foo",
+      get_host_override_string("foo.test.google.fr:1234", config), deadline,
+      NULL);
+  GPR_ASSERT(c);
+
+  grpc_metadata_array_init(&initial_metadata_recv);
+  grpc_metadata_array_init(&trailing_metadata_recv);
+  grpc_metadata_array_init(&request_metadata_recv);
+  grpc_call_details_init(&call_details);
+
+  memset(ops, 0, sizeof(ops));
+  op = ops;
+  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);
+  GPR_ASSERT(GRPC_CALL_OK == error);
+
+  memset(ops, 0, sizeof(ops));
+  op = ops;
+  op->op = GRPC_OP_RECV_INITIAL_METADATA;
+  op->data.recv_initial_metadata = &initial_metadata_recv;
+  op->flags = 0;
+  op->reserved = NULL;
+  op++;
+  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(2), NULL);
+  GPR_ASSERT(GRPC_CALL_OK == error);
+
+  GPR_ASSERT(GRPC_CALL_OK == grpc_server_request_call(
+                                 f.server, &s, &call_details,
+                                 &request_metadata_recv, f.cq, f.cq, tag(101)));
+  CQ_EXPECT_COMPLETION(cqv, tag(1), true); /* send message is buffered */
+  CQ_EXPECT_COMPLETION(cqv, tag(101), true);
+  cq_verify(cqv);
+
+  memset(ops, 0, sizeof(ops));
+  op = ops;
+  op->op = GRPC_OP_SEND_MESSAGE;
+  op->data.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);
+  GPR_ASSERT(GRPC_CALL_OK == error);
+
+  memset(ops, 0, sizeof(ops));
+  op = ops;
+  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);
+  GPR_ASSERT(GRPC_CALL_OK == error);
+
+  /* recv message should not succeed yet - it's buffered at the client still */
+  memset(ops, 0, sizeof(ops));
+  op = ops;
+  op->op = GRPC_OP_RECV_MESSAGE;
+  op->data.recv_message = &request_payload_recv1;
+  op++;
+  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(103), NULL);
+  GPR_ASSERT(GRPC_CALL_OK == error);
+
+  CQ_EXPECT_COMPLETION(cqv, tag(2), true);
+  CQ_EXPECT_COMPLETION(cqv, tag(3), true);
+  CQ_EXPECT_COMPLETION(cqv, tag(102), true);
+  cq_verify(cqv);
+
+  /* send end of stream: should release the buffering */
+  memset(ops, 0, sizeof(ops));
+  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);
+  GPR_ASSERT(GRPC_CALL_OK == error);
+
+  /* now the first send should match up with the first recv */
+  CQ_EXPECT_COMPLETION(cqv, tag(103), true);
+  CQ_EXPECT_COMPLETION(cqv, tag(4), true);
+  cq_verify(cqv);
+
+  /* and the next recv should be ready immediately also (and empty) */
+  memset(ops, 0, sizeof(ops));
+  op = ops;
+  op->op = GRPC_OP_RECV_MESSAGE;
+  op->data.recv_message = &request_payload_recv2;
+  op++;
+  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(104), NULL);
+  GPR_ASSERT(GRPC_CALL_OK == error);
+
+  CQ_EXPECT_COMPLETION(cqv, tag(104), true);
+  cq_verify(cqv);
+
+  memset(ops, 0, sizeof(ops));
+  op = ops;
+  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->data.recv_status_on_client.status_details_capacity = &details_capacity;
+  op->flags = 0;
+  op->reserved = NULL;
+  op++;
+  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(4), NULL);
+
+  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++;
+  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_OK;
+  op->data.send_status_from_server.status_details = "xyz";
+  op->flags = 0;
+  op->reserved = NULL;
+  op++;
+  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(105), NULL);
+  GPR_ASSERT(GRPC_CALL_OK == error);
+
+  CQ_EXPECT_COMPLETION(cqv, tag(105), 1);
+  CQ_EXPECT_COMPLETION(cqv, tag(4), 1);
+  cq_verify(cqv);
+
+  GPR_ASSERT(status == GRPC_STATUS_OK);
+  GPR_ASSERT(0 == strcmp(details, "xyz"));
+  GPR_ASSERT(0 == strcmp(call_details.method, "/foo"));
+  validate_host_override_string("foo.test.google.fr:1234", call_details.host,
+                                config);
+  GPR_ASSERT(was_cancelled == 0);
+  GPR_ASSERT(byte_buffer_eq_string(request_payload_recv1, "hello world"));
+  GPR_ASSERT(request_payload_recv2 == NULL);
+
+  gpr_free(details);
+  grpc_metadata_array_destroy(&initial_metadata_recv);
+  grpc_metadata_array_destroy(&trailing_metadata_recv);
+  grpc_metadata_array_destroy(&request_metadata_recv);
+  grpc_call_details_destroy(&call_details);
+
+  grpc_call_destroy(c);
+  grpc_call_destroy(s);
+
+  cq_verifier_destroy(cqv);
+
+  grpc_byte_buffer_destroy(request_payload);
+  grpc_byte_buffer_destroy(request_payload_recv1);
+
+  end_test(&f);
+  config.tear_down_data(&f);
+}
+
+void write_buffering_at_end(grpc_end2end_test_config config) {
+  test_invoke_request_with_payload(config);
+}
+
+void write_buffering_at_end_pre_init(void) {}