Merge branch 'master' into node_generator_nested_messages

7 files changed, 1089 insertions, 0 deletions

diff --git a/src/python/grpcio_tests/tests/unit/_cython/.gitignore b/src/python/grpcio_tests/tests/unit/_cython/.gitignore
new file mode 100644
index 0000000000..c315029288
--- /dev/null
+++ b/src/python/grpcio_tests/tests/unit/_cython/.gitignore
@@ -0,0 +1,7 @@
+*.h
+*.c
+*.a
+*.so
+*.dll
+*.pyc
+*.pyd
diff --git a/src/python/grpcio_tests/tests/unit/_cython/__init__.py b/src/python/grpcio_tests/tests/unit/_cython/__init__.py
new file mode 100644
index 0000000000..b89398809f
--- /dev/null
+++ b/src/python/grpcio_tests/tests/unit/_cython/__init__.py
@@ -0,0 +1,28 @@
+# Copyright 2015, 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.
diff --git a/src/python/grpcio_tests/tests/unit/_cython/_cancel_many_calls_test.py b/src/python/grpcio_tests/tests/unit/_cython/_cancel_many_calls_test.py
new file mode 100644
index 0000000000..cf212c5653
--- /dev/null
+++ b/src/python/grpcio_tests/tests/unit/_cython/_cancel_many_calls_test.py
@@ -0,0 +1,222 @@
+# Copyright 2016, 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.
+
+"""Test making many calls and immediately cancelling most of them."""
+
+import threading
+import unittest
+
+from grpc._cython import cygrpc
+from grpc.framework.foundation import logging_pool
+from tests.unit.framework.common import test_constants
+
+_INFINITE_FUTURE = cygrpc.Timespec(float('+inf'))
+_EMPTY_FLAGS = 0
+_EMPTY_METADATA = cygrpc.Metadata(())
+
+_SERVER_SHUTDOWN_TAG = 'server_shutdown'
+_REQUEST_CALL_TAG = 'request_call'
+_RECEIVE_CLOSE_ON_SERVER_TAG = 'receive_close_on_server'
+_RECEIVE_MESSAGE_TAG = 'receive_message'
+_SERVER_COMPLETE_CALL_TAG = 'server_complete_call'
+
+_SUCCESS_CALL_FRACTION = 1.0 / 8.0
+
+
+class _State(object):
+
+  def __init__(self):
+    self.condition = threading.Condition()
+    self.handlers_released = False
+    self.parked_handlers = 0
+    self.handled_rpcs = 0
+
+
+def _is_cancellation_event(event):
+  return (
+      event.tag is _RECEIVE_CLOSE_ON_SERVER_TAG and
+      event.batch_operations[0].received_cancelled)
+
+
+class _Handler(object):
+
+  def __init__(self, state, completion_queue, rpc_event):
+    self._state = state
+    self._lock = threading.Lock()
+    self._completion_queue = completion_queue
+    self._call = rpc_event.operation_call
+
+  def __call__(self):
+    with self._state.condition:
+      self._state.parked_handlers += 1
+      if self._state.parked_handlers == test_constants.THREAD_CONCURRENCY:
+        self._state.condition.notify_all()
+      while not self._state.handlers_released:
+        self._state.condition.wait()
+
+    with self._lock:
+      self._call.start_server_batch(
+          cygrpc.Operations(
+              (cygrpc.operation_receive_close_on_server(_EMPTY_FLAGS),)),
+          _RECEIVE_CLOSE_ON_SERVER_TAG)
+      self._call.start_server_batch(
+          cygrpc.Operations((cygrpc.operation_receive_message(_EMPTY_FLAGS),)),
+          _RECEIVE_MESSAGE_TAG)
+    first_event = self._completion_queue.poll()
+    if _is_cancellation_event(first_event):
+      self._completion_queue.poll()
+    else:
+      with self._lock:
+        operations = (
+            cygrpc.operation_send_initial_metadata(
+                _EMPTY_METADATA, _EMPTY_FLAGS),
+            cygrpc.operation_send_message(b'\x79\x57', _EMPTY_FLAGS),
+            cygrpc.operation_send_status_from_server(
+                _EMPTY_METADATA, cygrpc.StatusCode.ok, b'test details!',
+                _EMPTY_FLAGS),
+        )
+        self._call.start_server_batch(
+            cygrpc.Operations(operations), _SERVER_COMPLETE_CALL_TAG)
+      self._completion_queue.poll()
+      self._completion_queue.poll()
+
+
+def _serve(state, server, server_completion_queue, thread_pool):
+  for _ in range(test_constants.RPC_CONCURRENCY):
+    call_completion_queue = cygrpc.CompletionQueue()
+    server.request_call(
+        call_completion_queue, server_completion_queue, _REQUEST_CALL_TAG)
+    rpc_event = server_completion_queue.poll()
+    thread_pool.submit(_Handler(state, call_completion_queue, rpc_event))
+    with state.condition:
+      state.handled_rpcs += 1
+      if test_constants.RPC_CONCURRENCY <= state.handled_rpcs:
+        state.condition.notify_all()
+  server_completion_queue.poll()
+
+
+class _QueueDriver(object):
+
+  def __init__(self, condition, completion_queue, due):
+    self._condition = condition
+    self._completion_queue = completion_queue
+    self._due = due
+    self._events = []
+    self._returned = False
+
+  def start(self):
+    def in_thread():
+      while True:
+        event = self._completion_queue.poll()
+        with self._condition:
+          self._events.append(event)
+          self._due.remove(event.tag)
+          self._condition.notify_all()
+          if not self._due:
+            self._returned = True
+            return
+    thread = threading.Thread(target=in_thread)
+    thread.start()
+
+  def events(self, at_least):
+    with self._condition:
+      while len(self._events) < at_least:
+        self._condition.wait()
+      return tuple(self._events)
+
+
+class CancelManyCallsTest(unittest.TestCase):
+
+  def testCancelManyCalls(self):
+    server_thread_pool = logging_pool.pool(test_constants.THREAD_CONCURRENCY)
+
+    server_completion_queue = cygrpc.CompletionQueue()
+    server = cygrpc.Server()
+    server.register_completion_queue(server_completion_queue)
+    port = server.add_http2_port(b'[::]:0')
+    server.start()
+    channel = cygrpc.Channel('localhost:{}'.format(port).encode())
+
+    state = _State()
+
+    server_thread_args = (
+        state, server, server_completion_queue, server_thread_pool,)
+    server_thread = threading.Thread(target=_serve, args=server_thread_args)
+    server_thread.start()
+
+    client_condition = threading.Condition()
+    client_due = set()
+    client_completion_queue = cygrpc.CompletionQueue()
+    client_driver = _QueueDriver(
+        client_condition, client_completion_queue, client_due)
+    client_driver.start()
+
+    with client_condition:
+      client_calls = []
+      for index in range(test_constants.RPC_CONCURRENCY):
+        client_call = channel.create_call(
+            None, _EMPTY_FLAGS, client_completion_queue, b'/twinkies', None,
+            _INFINITE_FUTURE)
+        operations = (
+            cygrpc.operation_send_initial_metadata(
+                _EMPTY_METADATA, _EMPTY_FLAGS),
+            cygrpc.operation_send_message(b'\x45\x56', _EMPTY_FLAGS),
+            cygrpc.operation_send_close_from_client(_EMPTY_FLAGS),
+            cygrpc.operation_receive_initial_metadata(_EMPTY_FLAGS),
+            cygrpc.operation_receive_message(_EMPTY_FLAGS),
+            cygrpc.operation_receive_status_on_client(_EMPTY_FLAGS),
+        )
+        tag = 'client_complete_call_{0:04d}_tag'.format(index)
+        client_call.start_client_batch(cygrpc.Operations(operations), tag)
+        client_due.add(tag)
+        client_calls.append(client_call)
+
+    with state.condition:
+      while True:
+        if state.parked_handlers < test_constants.THREAD_CONCURRENCY:
+          state.condition.wait()
+        elif state.handled_rpcs < test_constants.RPC_CONCURRENCY:
+          state.condition.wait()
+        else:
+          state.handlers_released = True
+          state.condition.notify_all()
+          break
+
+    client_driver.events(
+        test_constants.RPC_CONCURRENCY * _SUCCESS_CALL_FRACTION)
+    with client_condition:
+      for client_call in client_calls:
+        client_call.cancel()
+
+    with state.condition:
+      server.shutdown(server_completion_queue, _SERVER_SHUTDOWN_TAG)
+
+
+if __name__ == '__main__':
+  unittest.main(verbosity=2)
diff --git a/src/python/grpcio_tests/tests/unit/_cython/_channel_test.py b/src/python/grpcio_tests/tests/unit/_cython/_channel_test.py
new file mode 100644
index 0000000000..f9c8a3ac62
--- /dev/null
+++ b/src/python/grpcio_tests/tests/unit/_cython/_channel_test.py
@@ -0,0 +1,82 @@
+# Copyright 2016, 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.
+
+import time
+import threading
+import unittest
+
+from grpc._cython import cygrpc
+
+from tests.unit.framework.common import test_constants
+
+
+def _channel_and_completion_queue():
+  channel = cygrpc.Channel(b'localhost:54321', cygrpc.ChannelArgs(()))
+  completion_queue = cygrpc.CompletionQueue()
+  return channel, completion_queue
+
+
+def _connectivity_loop(channel, completion_queue):
+  for _ in range(100):
+    connectivity = channel.check_connectivity_state(True)
+    channel.watch_connectivity_state(
+        connectivity, cygrpc.Timespec(time.time() + 0.2), completion_queue,
+        None)
+    completion_queue.poll(deadline=cygrpc.Timespec(float('+inf')))
+
+
+def _create_loop_destroy():
+  channel, completion_queue = _channel_and_completion_queue()
+  _connectivity_loop(channel, completion_queue)
+  completion_queue.shutdown()
+
+
+def _in_parallel(behavior, arguments):
+  threads = tuple(
+      threading.Thread(target=behavior, args=arguments)
+      for _ in range(test_constants.THREAD_CONCURRENCY))
+  for thread in threads:
+    thread.start()
+  for thread in threads:
+    thread.join()
+
+
+class ChannelTest(unittest.TestCase):
+
+  def test_single_channel_lonely_connectivity(self):
+    channel, completion_queue = _channel_and_completion_queue()
+    _in_parallel(_connectivity_loop, (channel, completion_queue,))
+    completion_queue.shutdown()
+
+  def test_multiple_channels_lonely_connectivity(self):
+    _in_parallel(_create_loop_destroy, ())
+
+
+if __name__ == '__main__':
+  unittest.main(verbosity=2)
diff --git a/src/python/grpcio_tests/tests/unit/_cython/_read_some_but_not_all_responses_test.py b/src/python/grpcio_tests/tests/unit/_cython/_read_some_but_not_all_responses_test.py
new file mode 100644
index 0000000000..152d8edde3
--- /dev/null
+++ b/src/python/grpcio_tests/tests/unit/_cython/_read_some_but_not_all_responses_test.py
@@ -0,0 +1,251 @@
+# Copyright 2016, 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.
+
+"""Test a corner-case at the level of the Cython API."""
+
+import threading
+import unittest
+
+from grpc._cython import cygrpc
+
+_INFINITE_FUTURE = cygrpc.Timespec(float('+inf'))
+_EMPTY_FLAGS = 0
+_EMPTY_METADATA = cygrpc.Metadata(())
+
+
+class _ServerDriver(object):
+
+  def __init__(self, completion_queue, shutdown_tag):
+    self._condition = threading.Condition()
+    self._completion_queue = completion_queue
+    self._shutdown_tag = shutdown_tag
+    self._events = []
+    self._saw_shutdown_tag = False
+
+  def start(self):
+    def in_thread():
+      while True:
+        event = self._completion_queue.poll()
+        with self._condition:
+          self._events.append(event)
+          self._condition.notify()
+          if event.tag is self._shutdown_tag:
+            self._saw_shutdown_tag = True
+            break
+    thread = threading.Thread(target=in_thread)
+    thread.start()
+
+  def done(self):
+    with self._condition:
+      return self._saw_shutdown_tag
+
+  def first_event(self):
+    with self._condition:
+      while not self._events:
+        self._condition.wait()
+      return self._events[0]
+
+  def events(self):
+    with self._condition:
+      while not self._saw_shutdown_tag:
+        self._condition.wait()
+      return tuple(self._events)
+
+
+class _QueueDriver(object):
+
+  def __init__(self, condition, completion_queue, due):
+    self._condition = condition
+    self._completion_queue = completion_queue
+    self._due = due
+    self._events = []
+    self._returned = False
+
+  def start(self):
+    def in_thread():
+      while True:
+        event = self._completion_queue.poll()
+        with self._condition:
+          self._events.append(event)
+          self._due.remove(event.tag)
+          self._condition.notify_all()
+          if not self._due:
+            self._returned = True
+            return
+    thread = threading.Thread(target=in_thread)
+    thread.start()
+
+  def done(self):
+    with self._condition:
+      return self._returned
+
+  def event_with_tag(self, tag):
+    with self._condition:
+      while True:
+        for event in self._events:
+          if event.tag is tag:
+            return event
+        self._condition.wait()
+
+  def events(self):
+    with self._condition:
+      while not self._returned:
+        self._condition.wait()
+      return tuple(self._events)
+
+
+class ReadSomeButNotAllResponsesTest(unittest.TestCase):
+
+  def testReadSomeButNotAllResponses(self):
+    server_completion_queue = cygrpc.CompletionQueue()
+    server = cygrpc.Server()
+    server.register_completion_queue(server_completion_queue)
+    port = server.add_http2_port(b'[::]:0')
+    server.start()
+    channel = cygrpc.Channel('localhost:{}'.format(port).encode())
+
+    server_shutdown_tag = 'server_shutdown_tag'
+    server_driver = _ServerDriver(server_completion_queue, server_shutdown_tag)
+    server_driver.start()
+
+    client_condition = threading.Condition()
+    client_due = set()
+    client_completion_queue = cygrpc.CompletionQueue()
+    client_driver = _QueueDriver(
+        client_condition, client_completion_queue, client_due)
+    client_driver.start()
+
+    server_call_condition = threading.Condition()
+    server_send_initial_metadata_tag = 'server_send_initial_metadata_tag'
+    server_send_first_message_tag = 'server_send_first_message_tag'
+    server_send_second_message_tag = 'server_send_second_message_tag'
+    server_complete_rpc_tag = 'server_complete_rpc_tag'
+    server_call_due = set((
+        server_send_initial_metadata_tag,
+        server_send_first_message_tag,
+        server_send_second_message_tag,
+        server_complete_rpc_tag,
+    ))
+    server_call_completion_queue = cygrpc.CompletionQueue()
+    server_call_driver = _QueueDriver(
+        server_call_condition, server_call_completion_queue, server_call_due)
+    server_call_driver.start()
+
+    server_rpc_tag = 'server_rpc_tag'
+    request_call_result = server.request_call(
+        server_call_completion_queue, server_completion_queue, server_rpc_tag)
+
+    client_call = channel.create_call(
+        None, _EMPTY_FLAGS, client_completion_queue, b'/twinkies', None,
+        _INFINITE_FUTURE)
+    client_receive_initial_metadata_tag = 'client_receive_initial_metadata_tag'
+    client_complete_rpc_tag = 'client_complete_rpc_tag'
+    with client_condition:
+      client_receive_initial_metadata_start_batch_result = (
+          client_call.start_client_batch(cygrpc.Operations([
+              cygrpc.operation_receive_initial_metadata(_EMPTY_FLAGS),
+          ]), client_receive_initial_metadata_tag))
+      client_due.add(client_receive_initial_metadata_tag)
+      client_complete_rpc_start_batch_result = (
+          client_call.start_client_batch(cygrpc.Operations([
+              cygrpc.operation_send_initial_metadata(
+                  _EMPTY_METADATA, _EMPTY_FLAGS),
+              cygrpc.operation_send_close_from_client(_EMPTY_FLAGS),
+              cygrpc.operation_receive_status_on_client(_EMPTY_FLAGS),
+          ]), client_complete_rpc_tag))
+      client_due.add(client_complete_rpc_tag)
+
+    server_rpc_event = server_driver.first_event()
+
+    with server_call_condition:
+      server_send_initial_metadata_start_batch_result = (
+          server_rpc_event.operation_call.start_server_batch([
+              cygrpc.operation_send_initial_metadata(
+                  _EMPTY_METADATA, _EMPTY_FLAGS),
+          ], server_send_initial_metadata_tag))
+      server_send_first_message_start_batch_result = (
+          server_rpc_event.operation_call.start_server_batch([
+              cygrpc.operation_send_message(b'\x07', _EMPTY_FLAGS),
+          ], server_send_first_message_tag))
+    server_send_initial_metadata_event = server_call_driver.event_with_tag(
+        server_send_initial_metadata_tag)
+    server_send_first_message_event = server_call_driver.event_with_tag(
+        server_send_first_message_tag)
+    with server_call_condition:
+      server_send_second_message_start_batch_result = (
+          server_rpc_event.operation_call.start_server_batch([
+              cygrpc.operation_send_message(b'\x07', _EMPTY_FLAGS),
+          ], server_send_second_message_tag))
+      server_complete_rpc_start_batch_result = (
+          server_rpc_event.operation_call.start_server_batch([
+              cygrpc.operation_receive_close_on_server(_EMPTY_FLAGS),
+              cygrpc.operation_send_status_from_server(
+                  cygrpc.Metadata(()), cygrpc.StatusCode.ok, b'test details',
+                  _EMPTY_FLAGS),
+          ], server_complete_rpc_tag))
+    server_send_second_message_event = server_call_driver.event_with_tag(
+        server_send_second_message_tag)
+    server_complete_rpc_event = server_call_driver.event_with_tag(
+        server_complete_rpc_tag)
+    server_call_driver.events()
+
+    with client_condition:
+      client_receive_first_message_tag = 'client_receive_first_message_tag'
+      client_receive_first_message_start_batch_result = (
+          client_call.start_client_batch(cygrpc.Operations([
+              cygrpc.operation_receive_message(_EMPTY_FLAGS),
+          ]), client_receive_first_message_tag))
+      client_due.add(client_receive_first_message_tag)
+    client_receive_first_message_event = client_driver.event_with_tag(
+        client_receive_first_message_tag)
+
+    client_call_cancel_result = client_call.cancel()
+    client_driver.events()
+
+    server.shutdown(server_completion_queue, server_shutdown_tag)
+    server.cancel_all_calls()
+    server_driver.events()
+
+    self.assertEqual(cygrpc.CallError.ok, request_call_result)
+    self.assertEqual(
+        cygrpc.CallError.ok, server_send_initial_metadata_start_batch_result)
+    self.assertEqual(
+        cygrpc.CallError.ok, client_receive_initial_metadata_start_batch_result)
+    self.assertEqual(
+        cygrpc.CallError.ok, client_complete_rpc_start_batch_result)
+    self.assertEqual(cygrpc.CallError.ok, client_call_cancel_result)
+    self.assertIs(server_rpc_tag, server_rpc_event.tag)
+    self.assertEqual(
+        cygrpc.CompletionType.operation_complete, server_rpc_event.type)
+    self.assertIsInstance(server_rpc_event.operation_call, cygrpc.Call)
+    self.assertEqual(0, len(server_rpc_event.batch_operations))
+
+
+if __name__ == '__main__':
+  unittest.main(verbosity=2)
diff --git a/src/python/grpcio_tests/tests/unit/_cython/cygrpc_test.py b/src/python/grpcio_tests/tests/unit/_cython/cygrpc_test.py
new file mode 100644
index 0000000000..f9a8e2401b
--- /dev/null
+++ b/src/python/grpcio_tests/tests/unit/_cython/cygrpc_test.py
@@ -0,0 +1,433 @@
+# Copyright 2015, 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.
+
+import time
+import threading
+import unittest
+
+from grpc._cython import cygrpc
+from tests.unit._cython import test_utilities
+from tests.unit import test_common
+from tests.unit import resources
+
+
+_SSL_HOST_OVERRIDE = b'foo.test.google.fr'
+_CALL_CREDENTIALS_METADATA_KEY = 'call-creds-key'
+_CALL_CREDENTIALS_METADATA_VALUE = 'call-creds-value'
+_EMPTY_FLAGS = 0
+
+def _metadata_plugin_callback(context, callback):
+  callback(cygrpc.Metadata(
+      [cygrpc.Metadatum(_CALL_CREDENTIALS_METADATA_KEY,
+                        _CALL_CREDENTIALS_METADATA_VALUE)]),
+      cygrpc.StatusCode.ok, b'')
+
+
+class TypeSmokeTest(unittest.TestCase):
+
+  def testStringsInUtilitiesUpDown(self):
+    self.assertEqual(0, cygrpc.StatusCode.ok)
+    metadatum = cygrpc.Metadatum(b'a', b'b')
+    self.assertEqual(b'a', metadatum.key)
+    self.assertEqual(b'b', metadatum.value)
+    metadata = cygrpc.Metadata([metadatum])
+    self.assertEqual(1, len(metadata))
+    self.assertEqual(metadatum.key, metadata[0].key)
+
+  def testMetadataIteration(self):
+    metadata = cygrpc.Metadata([
+        cygrpc.Metadatum(b'a', b'b'), cygrpc.Metadatum(b'c', b'd')])
+    iterator = iter(metadata)
+    metadatum = next(iterator)
+    self.assertIsInstance(metadatum, cygrpc.Metadatum)
+    self.assertEqual(metadatum.key, b'a')
+    self.assertEqual(metadatum.value, b'b')
+    metadatum = next(iterator)
+    self.assertIsInstance(metadatum, cygrpc.Metadatum)
+    self.assertEqual(metadatum.key, b'c')
+    self.assertEqual(metadatum.value, b'd')
+    with self.assertRaises(StopIteration):
+      next(iterator)
+
+  def testOperationsIteration(self):
+    operations = cygrpc.Operations([
+        cygrpc.operation_send_message(b'asdf', _EMPTY_FLAGS)])
+    iterator = iter(operations)
+    operation = next(iterator)
+    self.assertIsInstance(operation, cygrpc.Operation)
+    # `Operation`s are write-only structures; can't directly debug anything out
+    # of them. Just check that we stop iterating.
+    with self.assertRaises(StopIteration):
+      next(iterator)
+
+  def testOperationFlags(self):
+    operation = cygrpc.operation_send_message(b'asdf',
+                                              cygrpc.WriteFlag.no_compress)
+    self.assertEqual(cygrpc.WriteFlag.no_compress, operation.flags)
+
+  def testTimespec(self):
+    now = time.time()
+    timespec = cygrpc.Timespec(now)
+    self.assertAlmostEqual(now, float(timespec), places=8)
+
+  def testCompletionQueueUpDown(self):
+    completion_queue = cygrpc.CompletionQueue()
+    del completion_queue
+
+  def testServerUpDown(self):
+    server = cygrpc.Server(cygrpc.ChannelArgs([]))
+    del server
+
+  def testChannelUpDown(self):
+    channel = cygrpc.Channel(b'[::]:0', cygrpc.ChannelArgs([]))
+    del channel
+
+  def testCredentialsMetadataPluginUpDown(self):
+    plugin = cygrpc.CredentialsMetadataPlugin(
+        lambda ignored_a, ignored_b: None, b'')
+    del plugin
+
+  def testCallCredentialsFromPluginUpDown(self):
+    plugin = cygrpc.CredentialsMetadataPlugin(_metadata_plugin_callback, b'')
+    call_credentials = cygrpc.call_credentials_metadata_plugin(plugin)
+    del plugin
+    del call_credentials
+
+  def testServerStartNoExplicitShutdown(self):
+    server = cygrpc.Server()
+    completion_queue = cygrpc.CompletionQueue()
+    server.register_completion_queue(completion_queue)
+    port = server.add_http2_port(b'[::]:0')
+    self.assertIsInstance(port, int)
+    server.start()
+    del server
+
+  def testServerStartShutdown(self):
+    completion_queue = cygrpc.CompletionQueue()
+    server = cygrpc.Server()
+    server.add_http2_port(b'[::]:0')
+    server.register_completion_queue(completion_queue)
+    server.start()
+    shutdown_tag = object()
+    server.shutdown(completion_queue, shutdown_tag)
+    event = completion_queue.poll()
+    self.assertEqual(cygrpc.CompletionType.operation_complete, event.type)
+    self.assertIs(shutdown_tag, event.tag)
+    del server
+    del completion_queue
+
+
+class ServerClientMixin(object):
+
+  def setUpMixin(self, server_credentials, client_credentials, host_override):
+    self.server_completion_queue = cygrpc.CompletionQueue()
+    self.server = cygrpc.Server()
+    self.server.register_completion_queue(self.server_completion_queue)
+    if server_credentials:
+      self.port = self.server.add_http2_port(b'[::]:0', server_credentials)
+    else:
+      self.port = self.server.add_http2_port(b'[::]:0')
+    self.server.start()
+    self.client_completion_queue = cygrpc.CompletionQueue()
+    if client_credentials:
+      client_channel_arguments = cygrpc.ChannelArgs([
+          cygrpc.ChannelArg(cygrpc.ChannelArgKey.ssl_target_name_override,
+                            host_override)])
+      self.client_channel = cygrpc.Channel(
+          'localhost:{}'.format(self.port).encode(), client_channel_arguments,
+          client_credentials)
+    else:
+      self.client_channel = cygrpc.Channel('localhost:{}'.format(self.port).encode())
+    if host_override:
+      self.host_argument = None  # default host
+      self.expected_host = host_override
+    else:
+      # arbitrary host name necessitating no further identification
+      self.host_argument = b'hostess'
+      self.expected_host = self.host_argument
+
+  def tearDownMixin(self):
+    del self.server
+    del self.client_completion_queue
+    del self.server_completion_queue
+
+  def _perform_operations(self, operations, call, queue, deadline, description):
+    """Perform the list of operations with given call, queue, and deadline.
+
+    Invocation errors are reported with as an exception with `description` in
+    the message. Performs the operations asynchronously, returning a future.
+    """
+    def performer():
+      tag = object()
+      try:
+        call_result = call.start_client_batch(
+            cygrpc.Operations(operations), tag)
+        self.assertEqual(cygrpc.CallError.ok, call_result)
+        event = queue.poll(deadline)
+        self.assertEqual(cygrpc.CompletionType.operation_complete, event.type)
+        self.assertTrue(event.success)
+        self.assertIs(tag, event.tag)
+      except Exception as error:
+        raise Exception("Error in '{}': {}".format(description, error.message))
+      return event
+    return test_utilities.SimpleFuture(performer)
+
+  def testEcho(self):
+    DEADLINE = time.time()+5
+    DEADLINE_TOLERANCE = 0.25
+    CLIENT_METADATA_ASCII_KEY = b'key'
+    CLIENT_METADATA_ASCII_VALUE = b'val'
+    CLIENT_METADATA_BIN_KEY = b'key-bin'
+    CLIENT_METADATA_BIN_VALUE = b'\0'*1000
+    SERVER_INITIAL_METADATA_KEY = b'init_me_me_me'
+    SERVER_INITIAL_METADATA_VALUE = b'whodawha?'
+    SERVER_TRAILING_METADATA_KEY = b'california_is_in_a_drought'
+    SERVER_TRAILING_METADATA_VALUE = b'zomg it is'
+    SERVER_STATUS_CODE = cygrpc.StatusCode.ok
+    SERVER_STATUS_DETAILS = b'our work is never over'
+    REQUEST = b'in death a member of project mayhem has a name'
+    RESPONSE = b'his name is robert paulson'
+    METHOD = b'twinkies'
+
+    cygrpc_deadline = cygrpc.Timespec(DEADLINE)
+
+    server_request_tag = object()
+    request_call_result = self.server.request_call(
+        self.server_completion_queue, self.server_completion_queue,
+        server_request_tag)
+
+    self.assertEqual(cygrpc.CallError.ok, request_call_result)
+
+    client_call_tag = object()
+    client_call = self.client_channel.create_call(
+        None, 0, self.client_completion_queue, METHOD, self.host_argument,
+        cygrpc_deadline)
+    client_initial_metadata = cygrpc.Metadata([
+        cygrpc.Metadatum(CLIENT_METADATA_ASCII_KEY,
+                         CLIENT_METADATA_ASCII_VALUE),
+        cygrpc.Metadatum(CLIENT_METADATA_BIN_KEY, CLIENT_METADATA_BIN_VALUE)])
+    client_start_batch_result = client_call.start_client_batch([
+        cygrpc.operation_send_initial_metadata(client_initial_metadata,
+                                               _EMPTY_FLAGS),
+        cygrpc.operation_send_message(REQUEST, _EMPTY_FLAGS),
+        cygrpc.operation_send_close_from_client(_EMPTY_FLAGS),
+        cygrpc.operation_receive_initial_metadata(_EMPTY_FLAGS),
+        cygrpc.operation_receive_message(_EMPTY_FLAGS),
+        cygrpc.operation_receive_status_on_client(_EMPTY_FLAGS)
+    ], client_call_tag)
+    self.assertEqual(cygrpc.CallError.ok, client_start_batch_result)
+    client_event_future = test_utilities.CompletionQueuePollFuture(
+        self.client_completion_queue, cygrpc_deadline)
+
+    request_event = self.server_completion_queue.poll(cygrpc_deadline)
+    self.assertEqual(cygrpc.CompletionType.operation_complete,
+                      request_event.type)
+    self.assertIsInstance(request_event.operation_call, cygrpc.Call)
+    self.assertIs(server_request_tag, request_event.tag)
+    self.assertEqual(0, len(request_event.batch_operations))
+    self.assertTrue(
+        test_common.metadata_transmitted(client_initial_metadata,
+                                         request_event.request_metadata))
+    self.assertEqual(METHOD, request_event.request_call_details.method)
+    self.assertEqual(self.expected_host,
+                     request_event.request_call_details.host)
+    self.assertLess(
+        abs(DEADLINE - float(request_event.request_call_details.deadline)),
+        DEADLINE_TOLERANCE)
+
+    server_call_tag = object()
+    server_call = request_event.operation_call
+    server_initial_metadata = cygrpc.Metadata([
+        cygrpc.Metadatum(SERVER_INITIAL_METADATA_KEY,
+                         SERVER_INITIAL_METADATA_VALUE)])
+    server_trailing_metadata = cygrpc.Metadata([
+        cygrpc.Metadatum(SERVER_TRAILING_METADATA_KEY,
+                         SERVER_TRAILING_METADATA_VALUE)])
+    server_start_batch_result = server_call.start_server_batch([
+        cygrpc.operation_send_initial_metadata(server_initial_metadata,
+                                               _EMPTY_FLAGS),
+        cygrpc.operation_receive_message(_EMPTY_FLAGS),
+        cygrpc.operation_send_message(RESPONSE, _EMPTY_FLAGS),
+        cygrpc.operation_receive_close_on_server(_EMPTY_FLAGS),
+        cygrpc.operation_send_status_from_server(
+            server_trailing_metadata, SERVER_STATUS_CODE,
+            SERVER_STATUS_DETAILS, _EMPTY_FLAGS)
+    ], server_call_tag)
+    self.assertEqual(cygrpc.CallError.ok, server_start_batch_result)
+
+    server_event = self.server_completion_queue.poll(cygrpc_deadline)
+    client_event = client_event_future.result()
+
+    self.assertEqual(6, len(client_event.batch_operations))
+    found_client_op_types = set()
+    for client_result in client_event.batch_operations:
+      # we expect each op type to be unique
+      self.assertNotIn(client_result.type, found_client_op_types)
+      found_client_op_types.add(client_result.type)
+      if client_result.type == cygrpc.OperationType.receive_initial_metadata:
+        self.assertTrue(
+            test_common.metadata_transmitted(server_initial_metadata,
+                                             client_result.received_metadata))
+      elif client_result.type == cygrpc.OperationType.receive_message:
+        self.assertEqual(RESPONSE, client_result.received_message.bytes())
+      elif client_result.type == cygrpc.OperationType.receive_status_on_client:
+        self.assertTrue(
+            test_common.metadata_transmitted(server_trailing_metadata,
+                                             client_result.received_metadata))
+        self.assertEqual(SERVER_STATUS_DETAILS,
+                         client_result.received_status_details)
+        self.assertEqual(SERVER_STATUS_CODE, client_result.received_status_code)
+    self.assertEqual(set([
+          cygrpc.OperationType.send_initial_metadata,
+          cygrpc.OperationType.send_message,
+          cygrpc.OperationType.send_close_from_client,
+          cygrpc.OperationType.receive_initial_metadata,
+          cygrpc.OperationType.receive_message,
+          cygrpc.OperationType.receive_status_on_client
+      ]), found_client_op_types)
+
+    self.assertEqual(5, len(server_event.batch_operations))
+    found_server_op_types = set()
+    for server_result in server_event.batch_operations:
+      self.assertNotIn(client_result.type, found_server_op_types)
+      found_server_op_types.add(server_result.type)
+      if server_result.type == cygrpc.OperationType.receive_message:
+        self.assertEqual(REQUEST, server_result.received_message.bytes())
+      elif server_result.type == cygrpc.OperationType.receive_close_on_server:
+        self.assertFalse(server_result.received_cancelled)
+    self.assertEqual(set([
+          cygrpc.OperationType.send_initial_metadata,
+          cygrpc.OperationType.receive_message,
+          cygrpc.OperationType.send_message,
+          cygrpc.OperationType.receive_close_on_server,
+          cygrpc.OperationType.send_status_from_server
+      ]), found_server_op_types)
+
+    del client_call
+    del server_call
+
+  def test6522(self):
+    DEADLINE = time.time()+5
+    DEADLINE_TOLERANCE = 0.25
+    METHOD = b'twinkies'
+
+    cygrpc_deadline = cygrpc.Timespec(DEADLINE)
+    empty_metadata = cygrpc.Metadata([])
+
+    server_request_tag = object()
+    self.server.request_call(
+        self.server_completion_queue, self.server_completion_queue,
+        server_request_tag)
+    client_call = self.client_channel.create_call(
+        None, 0, self.client_completion_queue, METHOD, self.host_argument,
+        cygrpc_deadline)
+
+    # Prologue
+    def perform_client_operations(operations, description):
+      return self._perform_operations(
+          operations, client_call,
+          self.client_completion_queue, cygrpc_deadline, description)
+
+    client_event_future = perform_client_operations([
+            cygrpc.operation_send_initial_metadata(empty_metadata,
+                                                   _EMPTY_FLAGS),
+            cygrpc.operation_receive_initial_metadata(_EMPTY_FLAGS),
+        ], "Client prologue")
+
+    request_event = self.server_completion_queue.poll(cygrpc_deadline)
+    server_call = request_event.operation_call
+
+    def perform_server_operations(operations, description):
+      return self._perform_operations(
+          operations, server_call,
+          self.server_completion_queue, cygrpc_deadline, description)
+
+    server_event_future = perform_server_operations([
+            cygrpc.operation_send_initial_metadata(empty_metadata,
+                                                   _EMPTY_FLAGS),
+        ], "Server prologue")
+
+    client_event_future.result()  # force completion
+    server_event_future.result()
+
+    # Messaging
+    for _ in range(10):
+      client_event_future = perform_client_operations([
+              cygrpc.operation_send_message(b'', _EMPTY_FLAGS),
+              cygrpc.operation_receive_message(_EMPTY_FLAGS),
+          ], "Client message")
+      server_event_future = perform_server_operations([
+              cygrpc.operation_send_message(b'', _EMPTY_FLAGS),
+              cygrpc.operation_receive_message(_EMPTY_FLAGS),
+          ], "Server receive")
+
+      client_event_future.result()  # force completion
+      server_event_future.result()
+
+    # Epilogue
+    client_event_future = perform_client_operations([
+            cygrpc.operation_send_close_from_client(_EMPTY_FLAGS),
+            cygrpc.operation_receive_status_on_client(_EMPTY_FLAGS)
+        ], "Client epilogue")
+
+    server_event_future = perform_server_operations([
+            cygrpc.operation_receive_close_on_server(_EMPTY_FLAGS),
+            cygrpc.operation_send_status_from_server(
+                empty_metadata, cygrpc.StatusCode.ok, b'', _EMPTY_FLAGS)
+        ], "Server epilogue")
+
+    client_event_future.result()  # force completion
+    server_event_future.result()
+
+
+class InsecureServerInsecureClient(unittest.TestCase, ServerClientMixin):
+
+  def setUp(self):
+    self.setUpMixin(None, None, None)
+
+  def tearDown(self):
+    self.tearDownMixin()
+
+
+class SecureServerSecureClient(unittest.TestCase, ServerClientMixin):
+
+  def setUp(self):
+    server_credentials = cygrpc.server_credentials_ssl(
+        None, [cygrpc.SslPemKeyCertPair(resources.private_key(),
+                                        resources.certificate_chain())], False)
+    client_credentials = cygrpc.channel_credentials_ssl(
+        resources.test_root_certificates(), None)
+    self.setUpMixin(server_credentials, client_credentials, _SSL_HOST_OVERRIDE)
+
+  def tearDown(self):
+    self.tearDownMixin()
+
+
+if __name__ == '__main__':
+  unittest.main(verbosity=2)
diff --git a/src/python/grpcio_tests/tests/unit/_cython/test_utilities.py b/src/python/grpcio_tests/tests/unit/_cython/test_utilities.py
new file mode 100644
index 0000000000..6280ce74c4
--- /dev/null
+++ b/src/python/grpcio_tests/tests/unit/_cython/test_utilities.py
@@ -0,0 +1,66 @@
+# Copyright 2015, 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.
+
+import threading
+
+from grpc._cython import cygrpc
+
+
+class SimpleFuture(object):
+  """A simple future mechanism."""
+
+  def __init__(self, function, *args, **kwargs):
+    def wrapped_function():
+      try:
+        self._result = function(*args, **kwargs)
+      except Exception as error:
+        self._error = error
+    self._result = None
+    self._error = None
+    self._thread = threading.Thread(target=wrapped_function)
+    self._thread.start()
+
+  def result(self):
+    """The resulting value of this future.
+
+    Re-raises any exceptions.
+    """
+    self._thread.join()
+    if self._error:
+      # TODO(atash): re-raise exceptions in a way that preserves tracebacks
+      raise self._error
+    return self._result
+
+
+class CompletionQueuePollFuture(SimpleFuture):
+
+  def __init__(self, completion_queue, deadline):
+    super(CompletionQueuePollFuture, self).__init__(
+        lambda: completion_queue.poll(deadline))
+