Organize Python tests to use grpcio-tools directly

Moves all tests into a separate package. This does not change existing
supported means of running tests (e.g. through run_tests.py).

75 files changed, 11150 insertions, 0 deletions

diff --git a/src/python/grpcio_tests/tests/unit/__init__.py b/src/python/grpcio_tests/tests/unit/__init__.py
new file mode 100644
index 0000000000..7086519106
--- /dev/null
+++ b/src/python/grpcio_tests/tests/unit/__init__.py
@@ -0,0 +1,30 @@
+# 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/_adapter/.gitignore b/src/python/grpcio_tests/tests/unit/_adapter/.gitignore
new file mode 100644
index 0000000000..a6f96cd6db
--- /dev/null
+++ b/src/python/grpcio_tests/tests/unit/_adapter/.gitignore
@@ -0,0 +1,5 @@
+*.a
+*.so
+*.dll
+*.pyc
+*.pyd
diff --git a/src/python/grpcio_tests/tests/unit/_adapter/__init__.py b/src/python/grpcio_tests/tests/unit/_adapter/__init__.py
new file mode 100644
index 0000000000..7086519106
--- /dev/null
+++ b/src/python/grpcio_tests/tests/unit/_adapter/__init__.py
@@ -0,0 +1,30 @@
+# 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/_adapter/_proto_scenarios.py b/src/python/grpcio_tests/tests/unit/_adapter/_proto_scenarios.py
new file mode 100644
index 0000000000..7a90eacf77
--- /dev/null
+++ b/src/python/grpcio_tests/tests/unit/_adapter/_proto_scenarios.py
@@ -0,0 +1,262 @@
+# 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.
+
+"""Test scenarios using protocol buffers."""
+
+import abc
+import threading
+
+import six
+
+from tests.unit._junkdrawer import math_pb2
+
+
+class ProtoScenario(six.with_metaclass(abc.ABCMeta)):
+  """An RPC test scenario using protocol buffers."""
+
+  @abc.abstractmethod
+  def method(self):
+    """Access the test method name.
+
+    Returns:
+      The test method name.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def serialize_request(self, request):
+    """Serialize a request protocol buffer.
+
+    Args:
+      request: A request protocol buffer.
+
+    Returns:
+      The bytestring serialization of the given request protocol buffer.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def deserialize_request(self, request_bytestring):
+    """Deserialize a request protocol buffer.
+
+    Args:
+      request_bytestring: The bytestring serialization of a request protocol
+        buffer.
+
+    Returns:
+      The request protocol buffer deserialized from the given byte string.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def serialize_response(self, response):
+    """Serialize a response protocol buffer.
+
+    Args:
+      response: A response protocol buffer.
+
+    Returns:
+      The bytestring serialization of the given response protocol buffer.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def deserialize_response(self, response_bytestring):
+    """Deserialize a response protocol buffer.
+
+    Args:
+      response_bytestring: The bytestring serialization of a response protocol
+        buffer.
+
+    Returns:
+      The response protocol buffer deserialized from the given byte string.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def requests(self):
+    """Access the sequence of requests for this scenario.
+
+    Returns:
+      A sequence of request protocol buffers.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def response_for_request(self, request):
+    """Access the response for a particular request.
+
+    Args:
+      request: A request protocol buffer.
+
+    Returns:
+      The response protocol buffer appropriate for the given request.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def verify_requests(self, experimental_requests):
+    """Verify the requests transmitted through the system under test.
+
+    Args:
+      experimental_requests: The request protocol buffers transmitted through
+        the system under test.
+
+    Returns:
+      True if the requests satisfy this test scenario; False otherwise.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def verify_responses(self, experimental_responses):
+    """Verify the responses transmitted through the system under test.
+
+    Args:
+      experimental_responses: The response protocol buffers transmitted through
+        the system under test.
+
+    Returns:
+      True if the responses satisfy this test scenario; False otherwise.
+    """
+    raise NotImplementedError()
+
+
+class EmptyScenario(ProtoScenario):
+  """A scenario that transmits no protocol buffers in either direction."""
+
+  def method(self):
+    return 'DivMany'
+
+  def serialize_request(self, request):
+    raise ValueError('This should not be necessary to call!')
+
+  def deserialize_request(self, request_bytestring):
+    raise ValueError('This should not be necessary to call!')
+
+  def serialize_response(self, response):
+    raise ValueError('This should not be necessary to call!')
+
+  def deserialize_response(self, response_bytestring):
+    raise ValueError('This should not be necessary to call!')
+
+  def requests(self):
+    return ()
+
+  def response_for_request(self, request):
+    raise ValueError('This should not be necessary to call!')
+
+  def verify_requests(self, experimental_requests):
+    return not experimental_requests
+
+  def verify_responses(self, experimental_responses):
+    return not experimental_responses
+
+
+class BidirectionallyUnaryScenario(ProtoScenario):
+  """A scenario that transmits no protocol buffers in either direction."""
+
+  _DIVIDEND = 59
+  _DIVISOR = 7
+  _QUOTIENT = 8
+  _REMAINDER = 3
+
+  _REQUEST = math_pb2.DivArgs(dividend=_DIVIDEND, divisor=_DIVISOR)
+  _RESPONSE = math_pb2.DivReply(quotient=_QUOTIENT, remainder=_REMAINDER)
+
+  def method(self):
+    return 'Div'
+
+  def serialize_request(self, request):
+    return request.SerializeToString()
+
+  def deserialize_request(self, request_bytestring):
+    return math_pb2.DivArgs.FromString(request_bytestring)
+
+  def serialize_response(self, response):
+    return response.SerializeToString()
+
+  def deserialize_response(self, response_bytestring):
+    return math_pb2.DivReply.FromString(response_bytestring)
+
+  def requests(self):
+    return [self._REQUEST]
+
+  def response_for_request(self, request):
+    return self._RESPONSE
+
+  def verify_requests(self, experimental_requests):
+    return tuple(experimental_requests) == (self._REQUEST,)
+
+  def verify_responses(self, experimental_responses):
+    return tuple(experimental_responses) == (self._RESPONSE,)
+
+
+class BidirectionallyStreamingScenario(ProtoScenario):
+  """A scenario that transmits no protocol buffers in either direction."""
+
+  _STREAM_LENGTH = 200
+  _REQUESTS = tuple(
+      math_pb2.DivArgs(dividend=59 + index, divisor=7 + index)
+      for index in range(_STREAM_LENGTH))
+
+  def __init__(self):
+    self._lock = threading.Lock()
+    self._responses = []
+
+  def method(self):
+    return 'DivMany'
+
+  def serialize_request(self, request):
+    return request.SerializeToString()
+
+  def deserialize_request(self, request_bytestring):
+    return math_pb2.DivArgs.FromString(request_bytestring)
+
+  def serialize_response(self, response):
+    return response.SerializeToString()
+
+  def deserialize_response(self, response_bytestring):
+    return math_pb2.DivReply.FromString(response_bytestring)
+
+  def requests(self):
+    return self._REQUESTS
+
+  def response_for_request(self, request):
+    quotient, remainder = divmod(request.dividend, request.divisor)
+    response = math_pb2.DivReply(quotient=quotient, remainder=remainder)
+    with self._lock:
+      self._responses.append(response)
+    return response
+
+  def verify_requests(self, experimental_requests):
+    return tuple(experimental_requests) == self._REQUESTS
+
+  def verify_responses(self, experimental_responses):
+    with self._lock:
+      return tuple(experimental_responses) == tuple(self._responses)
diff --git a/src/python/grpcio_tests/tests/unit/_api_test.py b/src/python/grpcio_tests/tests/unit/_api_test.py
new file mode 100644
index 0000000000..2fe89499f5
--- /dev/null
+++ b/src/python/grpcio_tests/tests/unit/_api_test.py
@@ -0,0 +1,111 @@
+# 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 of gRPC Python's application-layer API."""
+
+import unittest
+
+import six
+
+import grpc
+
+from tests.unit import _from_grpc_import_star
+
+
+class AllTest(unittest.TestCase):
+
+  def testAll(self):
+    expected_grpc_code_elements = (
+        'FutureTimeoutError',
+        'FutureCancelledError',
+        'Future',
+        'ChannelConnectivity',
+        'StatusCode',
+        'RpcError',
+        'RpcContext',
+        'Call',
+        'ChannelCredentials',
+        'CallCredentials',
+        'AuthMetadataContext',
+        'AuthMetadataPluginCallback',
+        'AuthMetadataPlugin',
+        'ServerCredentials',
+        'UnaryUnaryMultiCallable',
+        'UnaryStreamMultiCallable',
+        'StreamUnaryMultiCallable',
+        'StreamStreamMultiCallable',
+        'Channel',
+        'ServicerContext',
+        'RpcMethodHandler',
+        'HandlerCallDetails',
+        'GenericRpcHandler',
+        'Server',
+        'unary_unary_rpc_method_handler',
+        'unary_stream_rpc_method_handler',
+        'stream_unary_rpc_method_handler',
+        'stream_stream_rpc_method_handler',
+        'method_handlers_generic_handler',
+        'ssl_channel_credentials',
+        'metadata_call_credentials',
+        'access_token_call_credentials',
+        'composite_call_credentials',
+        'composite_channel_credentials',
+        'ssl_server_credentials',
+        'channel_ready_future',
+        'insecure_channel',
+        'secure_channel',
+        'server',
+    )
+
+    six.assertCountEqual(
+        self, expected_grpc_code_elements,
+        _from_grpc_import_star.GRPC_ELEMENTS)
+
+
+class ChannelConnectivityTest(unittest.TestCase):
+
+  def testChannelConnectivity(self):
+    self.assertSequenceEqual(
+        (grpc.ChannelConnectivity.IDLE,
+         grpc.ChannelConnectivity.CONNECTING,
+         grpc.ChannelConnectivity.READY,
+         grpc.ChannelConnectivity.TRANSIENT_FAILURE,
+         grpc.ChannelConnectivity.SHUTDOWN,),
+        tuple(grpc.ChannelConnectivity))
+
+
+class ChannelTest(unittest.TestCase):
+
+  def test_secure_channel(self):
+    channel_credentials = grpc.ssl_channel_credentials()
+    channel = grpc.secure_channel('google.com:443', channel_credentials)
+
+
+if __name__ == '__main__':
+  unittest.main(verbosity=2)
diff --git a/src/python/grpcio_tests/tests/unit/_auth_test.py b/src/python/grpcio_tests/tests/unit/_auth_test.py
new file mode 100644
index 0000000000..c31f7b06f7
--- /dev/null
+++ b/src/python/grpcio_tests/tests/unit/_auth_test.py
@@ -0,0 +1,96 @@
+# 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.
+
+"""Tests of standard AuthMetadataPlugins."""
+
+import collections
+import threading
+import unittest
+
+from grpc import _auth
+
+
+class MockGoogleCreds(object):
+
+  def get_access_token(self):
+    token = collections.namedtuple('MockAccessTokenInfo',
+                                   ('access_token', 'expires_in'))
+    token.access_token = 'token'
+    return token
+
+
+class MockExceptionGoogleCreds(object):
+
+  def get_access_token(self):
+    raise Exception()
+
+
+class GoogleCallCredentialsTest(unittest.TestCase):
+
+  def test_google_call_credentials_success(self):
+    callback_event = threading.Event()
+
+    def mock_callback(metadata, error):
+      self.assertEqual(metadata, (('authorization', 'Bearer token'),))
+      self.assertIsNone(error)
+      callback_event.set()
+
+    call_creds = _auth.GoogleCallCredentials(MockGoogleCreds())
+    call_creds(None, mock_callback)
+    self.assertTrue(callback_event.wait(1.0))
+
+  def test_google_call_credentials_error(self):
+    callback_event = threading.Event()
+
+    def mock_callback(metadata, error):
+      self.assertIsNotNone(error)
+      callback_event.set()
+
+    call_creds = _auth.GoogleCallCredentials(MockExceptionGoogleCreds())
+    call_creds(None, mock_callback)
+    self.assertTrue(callback_event.wait(1.0))
+
+
+class AccessTokenCallCredentialsTest(unittest.TestCase):
+
+  def test_google_call_credentials_success(self):
+    callback_event = threading.Event()
+
+    def mock_callback(metadata, error):
+      self.assertEqual(metadata, (('authorization', 'Bearer token'),))
+      self.assertIsNone(error)
+      callback_event.set()
+
+    call_creds = _auth.AccessTokenCallCredentials('token')
+    call_creds(None, mock_callback)
+    self.assertTrue(callback_event.wait(1.0))
+
+
+if __name__ == '__main__':
+  unittest.main(verbosity=2)
diff --git a/src/python/grpcio_tests/tests/unit/_channel_connectivity_test.py b/src/python/grpcio_tests/tests/unit/_channel_connectivity_test.py
new file mode 100644
index 0000000000..ae8de523ec
--- /dev/null
+++ b/src/python/grpcio_tests/tests/unit/_channel_connectivity_test.py
@@ -0,0 +1,161 @@
+# 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.
+
+"""Tests of grpc._channel.Channel connectivity."""
+
+import threading
+import time
+import unittest
+from concurrent import futures
+
+import grpc
+from grpc import _channel
+from grpc import _server
+from tests.unit.framework.common import test_constants
+
+
+def _ready_in_connectivities(connectivities):
+  return grpc.ChannelConnectivity.READY in connectivities
+
+
+def _last_connectivity_is_not_ready(connectivities):
+  return connectivities[-1] is not grpc.ChannelConnectivity.READY
+
+
+class _Callback(object):
+
+  def __init__(self):
+    self._condition = threading.Condition()
+    self._connectivities = []
+
+  def update(self, connectivity):
+    with self._condition:
+      self._connectivities.append(connectivity)
+      self._condition.notify()
+
+  def connectivities(self):
+    with self._condition:
+      return tuple(self._connectivities)
+
+  def block_until_connectivities_satisfy(self, predicate):
+    with self._condition:
+      while True:
+        connectivities = tuple(self._connectivities)
+        if predicate(connectivities):
+          return connectivities
+        else:
+          self._condition.wait()
+
+
+class ChannelConnectivityTest(unittest.TestCase):
+
+  def test_lonely_channel_connectivity(self):
+    callback = _Callback()
+
+    channel = _channel.Channel('localhost:12345', None, None)
+    channel.subscribe(callback.update, try_to_connect=False)
+    first_connectivities = callback.block_until_connectivities_satisfy(bool)
+    channel.subscribe(callback.update, try_to_connect=True)
+    second_connectivities = callback.block_until_connectivities_satisfy(
+        lambda connectivities: 2 <= len(connectivities))
+    # Wait for a connection that will never happen.
+    time.sleep(test_constants.SHORT_TIMEOUT)
+    third_connectivities = callback.connectivities()
+    channel.unsubscribe(callback.update)
+    fourth_connectivities = callback.connectivities()
+    channel.unsubscribe(callback.update)
+    fifth_connectivities = callback.connectivities()
+
+    self.assertSequenceEqual(
+        (grpc.ChannelConnectivity.IDLE,), first_connectivities)
+    self.assertNotIn(
+        grpc.ChannelConnectivity.READY, second_connectivities)
+    self.assertNotIn(
+        grpc.ChannelConnectivity.READY, third_connectivities)
+    self.assertNotIn(
+        grpc.ChannelConnectivity.READY, fourth_connectivities)
+    self.assertNotIn(
+        grpc.ChannelConnectivity.READY, fifth_connectivities)
+
+  def test_immediately_connectable_channel_connectivity(self):
+    server = _server.Server((), futures.ThreadPoolExecutor(max_workers=0))
+    port = server.add_insecure_port('[::]:0')
+    server.start()
+    first_callback = _Callback()
+    second_callback = _Callback()
+
+    channel = _channel.Channel('localhost:{}'.format(port), None, None)
+    channel.subscribe(first_callback.update, try_to_connect=False)
+    first_connectivities = first_callback.block_until_connectivities_satisfy(
+        bool)
+    # Wait for a connection that will never happen because try_to_connect=True
+    # has not yet been passed.
+    time.sleep(test_constants.SHORT_TIMEOUT)
+    second_connectivities = first_callback.connectivities()
+    channel.subscribe(second_callback.update, try_to_connect=True)
+    third_connectivities = first_callback.block_until_connectivities_satisfy(
+        lambda connectivities: 2 <= len(connectivities))
+    fourth_connectivities = second_callback.block_until_connectivities_satisfy(
+        bool)
+    # Wait for a connection that will happen (or may already have happened).
+    first_callback.block_until_connectivities_satisfy(_ready_in_connectivities)
+    second_callback.block_until_connectivities_satisfy(_ready_in_connectivities)
+    del channel
+
+    self.assertSequenceEqual(
+        (grpc.ChannelConnectivity.IDLE,), first_connectivities)
+    self.assertSequenceEqual(
+        (grpc.ChannelConnectivity.IDLE,), second_connectivities)
+    self.assertNotIn(
+        grpc.ChannelConnectivity.TRANSIENT_FAILURE, third_connectivities)
+    self.assertNotIn(
+        grpc.ChannelConnectivity.SHUTDOWN, third_connectivities)
+    self.assertNotIn(
+        grpc.ChannelConnectivity.TRANSIENT_FAILURE,
+        fourth_connectivities)
+    self.assertNotIn(
+        grpc.ChannelConnectivity.SHUTDOWN, fourth_connectivities)
+
+  def test_reachable_then_unreachable_channel_connectivity(self):
+    server = _server.Server((), futures.ThreadPoolExecutor(max_workers=0))
+    port = server.add_insecure_port('[::]:0')
+    server.start()
+    callback = _Callback()
+
+    channel = _channel.Channel('localhost:{}'.format(port), None, None)
+    channel.subscribe(callback.update, try_to_connect=True)
+    callback.block_until_connectivities_satisfy(_ready_in_connectivities)
+    # Now take down the server and confirm that channel readiness is repudiated.
+    server.stop(None)
+    callback.block_until_connectivities_satisfy(_last_connectivity_is_not_ready)
+    channel.unsubscribe(callback.update)
+
+
+if __name__ == '__main__':
+  unittest.main(verbosity=2)
diff --git a/src/python/grpcio_tests/tests/unit/_channel_ready_future_test.py b/src/python/grpcio_tests/tests/unit/_channel_ready_future_test.py
new file mode 100644
index 0000000000..b84bc0197a
--- /dev/null
+++ b/src/python/grpcio_tests/tests/unit/_channel_ready_future_test.py
@@ -0,0 +1,103 @@
+# 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.
+
+"""Tests of grpc.channel_ready_future."""
+
+import threading
+import unittest
+from concurrent import futures
+
+import grpc
+from grpc import _channel
+from grpc import _server
+from tests.unit.framework.common import test_constants
+
+
+class _Callback(object):
+
+  def __init__(self):
+    self._condition = threading.Condition()
+    self._value = None
+
+  def accept_value(self, value):
+    with self._condition:
+      self._value = value
+      self._condition.notify_all()
+
+  def block_until_called(self):
+    with self._condition:
+      while self._value is None:
+        self._condition.wait()
+      return self._value
+
+
+class ChannelReadyFutureTest(unittest.TestCase):
+
+  def test_lonely_channel_connectivity(self):
+    channel = grpc.insecure_channel('localhost:12345')
+    callback = _Callback()
+
+    ready_future = grpc.channel_ready_future(channel)
+    ready_future.add_done_callback(callback.accept_value)
+    with self.assertRaises(grpc.FutureTimeoutError):
+      ready_future.result(test_constants.SHORT_TIMEOUT)
+    self.assertFalse(ready_future.cancelled())
+    self.assertFalse(ready_future.done())
+    self.assertTrue(ready_future.running())
+    ready_future.cancel()
+    value_passed_to_callback = callback.block_until_called()
+    self.assertIs(ready_future, value_passed_to_callback)
+    self.assertTrue(ready_future.cancelled())
+    self.assertTrue(ready_future.done())
+    self.assertFalse(ready_future.running())
+
+  def test_immediately_connectable_channel_connectivity(self):
+    server = _server.Server((), futures.ThreadPoolExecutor(max_workers=0))
+    port = server.add_insecure_port('[::]:0')
+    server.start()
+    channel = grpc.insecure_channel('localhost:{}'.format(port))
+    callback = _Callback()
+
+    ready_future = grpc.channel_ready_future(channel)
+    ready_future.add_done_callback(callback.accept_value)
+    self.assertIsNone(ready_future.result(test_constants.SHORT_TIMEOUT))
+    value_passed_to_callback = callback.block_until_called()
+    self.assertIs(ready_future, value_passed_to_callback)
+    self.assertFalse(ready_future.cancelled())
+    self.assertTrue(ready_future.done())
+    self.assertFalse(ready_future.running())
+    # Cancellation after maturity has no effect.
+    ready_future.cancel()
+    self.assertFalse(ready_future.cancelled())
+    self.assertTrue(ready_future.done())
+    self.assertFalse(ready_future.running())
+
+
+if __name__ == '__main__':
+  unittest.main(verbosity=2)
diff --git a/src/python/grpcio_tests/tests/unit/_compression_test.py b/src/python/grpcio_tests/tests/unit/_compression_test.py
new file mode 100644
index 0000000000..9e8b8578c1
--- /dev/null
+++ b/src/python/grpcio_tests/tests/unit/_compression_test.py
@@ -0,0 +1,133 @@
+# 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.
+"""Tests server and client side compression."""
+
+import unittest
+
+import grpc
+from grpc import _grpcio_metadata
+from grpc.framework.foundation import logging_pool
+
+from tests.unit import test_common
+from tests.unit.framework.common import test_constants
+
+_UNARY_UNARY = '/test/UnaryUnary'
+_STREAM_STREAM = '/test/StreamStream'
+
+
+def handle_unary(request, servicer_context):
+  servicer_context.send_initial_metadata([
+    ('grpc-internal-encoding-request', 'gzip')])
+  return request
+
+
+def handle_stream(request_iterator, servicer_context):
+  # TODO(issue:#6891) We should be able to remove this loop,
+  # and replace with return; yield
+  servicer_context.send_initial_metadata([
+    ('grpc-internal-encoding-request', 'gzip')])
+  for request in request_iterator:
+    yield request
+
+
+class _MethodHandler(grpc.RpcMethodHandler):
+
+  def __init__(self, request_streaming, response_streaming):
+    self.request_streaming = request_streaming
+    self.response_streaming = response_streaming
+    self.request_deserializer = None
+    self.response_serializer = None
+    self.unary_unary = None
+    self.unary_stream = None
+    self.stream_unary = None
+    self.stream_stream = None
+    if self.request_streaming and self.response_streaming:
+      self.stream_stream = lambda x, y: handle_stream(x, y)
+    elif not self.request_streaming and not self.response_streaming:
+      self.unary_unary = lambda x, y: handle_unary(x, y)
+
+
+class _GenericHandler(grpc.GenericRpcHandler):
+
+  def service(self, handler_call_details):
+    if handler_call_details.method == _UNARY_UNARY:
+      return _MethodHandler(False, False)
+    elif handler_call_details.method == _STREAM_STREAM:
+      return _MethodHandler(True, True)
+    else:
+      return None
+
+
+class CompressionTest(unittest.TestCase):
+
+  def setUp(self):
+    self._server_pool = logging_pool.pool(test_constants.THREAD_CONCURRENCY)
+    self._server = grpc.server((_GenericHandler(),), self._server_pool)
+    self._port = self._server.add_insecure_port('[::]:0')
+    self._server.start()
+
+  def testUnary(self):
+    request = b'\x00' * 100
+
+    # Client -> server compressed through default client channel compression
+    # settings. Server -> client compressed via server-side metadata setting.
+    # TODO(https://github.com/grpc/grpc/issues/4078): replace the "1" integer
+    # literal with proper use of the public API.
+    compressed_channel = grpc.insecure_channel('localhost:%d' % self._port,
+        options=[('grpc.default_compression_algorithm', 1)])
+    multi_callable = compressed_channel.unary_unary(_UNARY_UNARY)
+    response = multi_callable(request)
+    self.assertEqual(request, response)
+
+    # Client -> server compressed through client metadata setting. Server ->
+    # client compressed via server-side metadata setting.
+    # TODO(https://github.com/grpc/grpc/issues/4078): replace the "0" integer
+    # literal with proper use of the public API.
+    uncompressed_channel = grpc.insecure_channel('localhost:%d' % self._port,
+        options=[('grpc.default_compression_algorithm', 0)])
+    multi_callable = compressed_channel.unary_unary(_UNARY_UNARY)
+    response = multi_callable(request, metadata=[
+      ('grpc-internal-encoding-request', 'gzip')])
+    self.assertEqual(request, response)
+
+  def testStreaming(self):
+    request = b'\x00' * 100
+
+    # TODO(https://github.com/grpc/grpc/issues/4078): replace the "1" integer
+    # literal with proper use of the public API.
+    compressed_channel = grpc.insecure_channel('localhost:%d' % self._port,
+        options=[('grpc.default_compression_algorithm', 1)])
+    multi_callable = compressed_channel.stream_stream(_STREAM_STREAM)
+    call = multi_callable([request] * test_constants.STREAM_LENGTH)
+    for response in call:
+      self.assertEqual(request, response)
+
+
+if __name__ == '__main__':
+  unittest.main(verbosity=2)
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..cac0c8b3b9
--- /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_batch(
+          cygrpc.Operations(
+              (cygrpc.operation_receive_close_on_server(_EMPTY_FLAGS),)),
+          _RECEIVE_CLOSE_ON_SERVER_TAG)
+      self._call.start_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_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_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..27fcee0d6f
--- /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_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_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_batch(cygrpc.Operations([
+              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_batch(cygrpc.Operations([
+              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_batch(cygrpc.Operations([
+              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_batch(cygrpc.Operations([
+              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_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..b740695e35
--- /dev/null
+++ b/src/python/grpcio_tests/tests/unit/_cython/cygrpc_test.py
@@ -0,0 +1,432 @@
+# 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_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_batch(cygrpc.Operations([
+        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_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)
+
+    client_event = client_event_future.result()
+    server_event = self.server_completion_queue.poll(cygrpc_deadline)
+
+    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))
+
diff --git a/src/python/grpcio_tests/tests/unit/_empty_message_test.py b/src/python/grpcio_tests/tests/unit/_empty_message_test.py
new file mode 100644
index 0000000000..8c7d697728
--- /dev/null
+++ b/src/python/grpcio_tests/tests/unit/_empty_message_test.py
@@ -0,0 +1,137 @@
+# 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 unittest
+
+import grpc
+from grpc.framework.foundation import logging_pool
+
+from tests.unit.framework.common import test_constants
+
+_REQUEST = b''
+_RESPONSE = b''
+
+_UNARY_UNARY = '/test/UnaryUnary'
+_UNARY_STREAM = '/test/UnaryStream'
+_STREAM_UNARY = '/test/StreamUnary'
+_STREAM_STREAM = '/test/StreamStream'
+
+
+def handle_unary_unary(request, servicer_context):
+  return _RESPONSE
+
+
+def handle_unary_stream(request, servicer_context):
+  for _ in range(test_constants.STREAM_LENGTH):
+    yield _RESPONSE
+
+
+def handle_stream_unary(request_iterator, servicer_context):
+  for request in request_iterator:
+    pass
+  return _RESPONSE
+
+
+def handle_stream_stream(request_iterator, servicer_context):
+  for request in request_iterator:
+    yield _RESPONSE
+
+
+class _MethodHandler(grpc.RpcMethodHandler):
+
+  def __init__(self, request_streaming, response_streaming):
+    self.request_streaming = request_streaming
+    self.response_streaming = response_streaming
+    self.request_deserializer = None
+    self.response_serializer = None
+    self.unary_unary = None
+    self.unary_stream = None
+    self.stream_unary = None
+    self.stream_stream = None
+    if self.request_streaming and self.response_streaming:
+      self.stream_stream = handle_stream_stream
+    elif self.request_streaming:
+      self.stream_unary = handle_stream_unary
+    elif self.response_streaming:
+      self.unary_stream = handle_unary_stream
+    else:
+      self.unary_unary = handle_unary_unary
+
+
+class _GenericHandler(grpc.GenericRpcHandler):
+
+  def service(self, handler_call_details):
+    if handler_call_details.method == _UNARY_UNARY:
+      return _MethodHandler(False, False)
+    elif handler_call_details.method == _UNARY_STREAM:
+      return _MethodHandler(False, True)
+    elif handler_call_details.method == _STREAM_UNARY:
+      return _MethodHandler(True, False)
+    elif handler_call_details.method == _STREAM_STREAM:
+      return _MethodHandler(True, True)
+    else:
+      return None
+
+
+class EmptyMessageTest(unittest.TestCase):
+
+  def setUp(self):
+    self._server_pool = logging_pool.pool(test_constants.THREAD_CONCURRENCY)
+    self._server = grpc.server((_GenericHandler(),), self._server_pool)
+    port = self._server.add_insecure_port('[::]:0')
+    self._server.start()
+    self._channel = grpc.insecure_channel('localhost:%d' % port)
+
+  def tearDown(self):
+    self._server.stop(0)
+
+  def testUnaryUnary(self):
+    response = self._channel.unary_unary(_UNARY_UNARY)(_REQUEST)
+    self.assertEqual(_RESPONSE, response)
+
+  def testUnaryStream(self):
+    response_iterator = self._channel.unary_stream(_UNARY_STREAM)(_REQUEST)
+    self.assertSequenceEqual(
+        [_RESPONSE] * test_constants.STREAM_LENGTH, list(response_iterator))
+
+  def testStreamUnary(self):
+    response = self._channel.stream_unary(_STREAM_UNARY)(
+        [_REQUEST] * test_constants.STREAM_LENGTH)
+    self.assertEqual(_RESPONSE, response)
+
+  def testStreamStream(self):
+    response_iterator = self._channel.stream_stream(_STREAM_STREAM)(
+        [_REQUEST] * test_constants.STREAM_LENGTH)
+    self.assertSequenceEqual(
+        [_RESPONSE] * test_constants.STREAM_LENGTH, list(response_iterator))
+
+
+if __name__ == '__main__':
+  unittest.main(verbosity=2)
+
diff --git a/src/python/grpcio_tests/tests/unit/_exit_scenarios.py b/src/python/grpcio_tests/tests/unit/_exit_scenarios.py
new file mode 100644
index 0000000000..24a2faef85
--- /dev/null
+++ b/src/python/grpcio_tests/tests/unit/_exit_scenarios.py
@@ -0,0 +1,249 @@
+# 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.
+
+"""Defines a number of module-scope gRPC scenarios to test clean exit."""
+
+import argparse
+import threading
+import time
+
+import grpc
+
+from tests.unit.framework.common import test_constants
+
+WAIT_TIME = 1000
+
+REQUEST = b'request'
+
+UNSTARTED_SERVER = 'unstarted_server'
+RUNNING_SERVER = 'running_server'
+POLL_CONNECTIVITY_NO_SERVER = 'poll_connectivity_no_server'
+POLL_CONNECTIVITY = 'poll_connectivity'
+IN_FLIGHT_UNARY_UNARY_CALL = 'in_flight_unary_unary_call'
+IN_FLIGHT_UNARY_STREAM_CALL = 'in_flight_unary_stream_call'
+IN_FLIGHT_STREAM_UNARY_CALL = 'in_flight_stream_unary_call'
+IN_FLIGHT_STREAM_STREAM_CALL = 'in_flight_stream_stream_call'
+IN_FLIGHT_PARTIAL_UNARY_STREAM_CALL = 'in_flight_partial_unary_stream_call'
+IN_FLIGHT_PARTIAL_STREAM_UNARY_CALL = 'in_flight_partial_stream_unary_call'
+IN_FLIGHT_PARTIAL_STREAM_STREAM_CALL = 'in_flight_partial_stream_stream_call'
+
+UNARY_UNARY = b'/test/UnaryUnary'
+UNARY_STREAM = b'/test/UnaryStream'
+STREAM_UNARY = b'/test/StreamUnary'
+STREAM_STREAM = b'/test/StreamStream'
+PARTIAL_UNARY_STREAM = b'/test/PartialUnaryStream'
+PARTIAL_STREAM_UNARY = b'/test/PartialStreamUnary'
+PARTIAL_STREAM_STREAM = b'/test/PartialStreamStream'
+
+TEST_TO_METHOD = {
+    IN_FLIGHT_UNARY_UNARY_CALL: UNARY_UNARY,
+    IN_FLIGHT_UNARY_STREAM_CALL: UNARY_STREAM,
+    IN_FLIGHT_STREAM_UNARY_CALL: STREAM_UNARY,
+    IN_FLIGHT_STREAM_STREAM_CALL: STREAM_STREAM,
+    IN_FLIGHT_PARTIAL_UNARY_STREAM_CALL: PARTIAL_UNARY_STREAM,
+    IN_FLIGHT_PARTIAL_STREAM_UNARY_CALL: PARTIAL_STREAM_UNARY,
+    IN_FLIGHT_PARTIAL_STREAM_STREAM_CALL: PARTIAL_STREAM_STREAM,
+}
+
+
+def hang_unary_unary(request, servicer_context):
+  time.sleep(WAIT_TIME)
+
+
+def hang_unary_stream(request, servicer_context):
+  time.sleep(WAIT_TIME)
+
+
+def hang_partial_unary_stream(request, servicer_context):
+  for _ in range(test_constants.STREAM_LENGTH // 2):
+    yield request
+  time.sleep(WAIT_TIME)
+
+
+def hang_stream_unary(request_iterator, servicer_context):
+  time.sleep(WAIT_TIME)
+
+
+def hang_partial_stream_unary(request_iterator, servicer_context):
+  for _ in range(test_constants.STREAM_LENGTH // 2):
+    next(request_iterator)
+  time.sleep(WAIT_TIME)
+
+
+def hang_stream_stream(request_iterator, servicer_context):
+  time.sleep(WAIT_TIME)
+
+
+def hang_partial_stream_stream(request_iterator, servicer_context):
+  for _ in range(test_constants.STREAM_LENGTH // 2):
+    yield next(request_iterator)
+  time.sleep(WAIT_TIME)
+
+
+class MethodHandler(grpc.RpcMethodHandler):
+
+  def __init__(self, request_streaming, response_streaming, partial_hang):
+    self.request_streaming = request_streaming
+    self.response_streaming = response_streaming
+    self.request_deserializer = None
+    self.response_serializer = None
+    self.unary_unary = None
+    self.unary_stream = None
+    self.stream_unary = None
+    self.stream_stream = None
+    if self.request_streaming and self.response_streaming:
+      if partial_hang:
+        self.stream_stream = hang_partial_stream_stream
+      else:
+        self.stream_stream = hang_stream_stream
+    elif self.request_streaming:
+      if partial_hang:
+        self.stream_unary = hang_partial_stream_unary
+      else:
+        self.stream_unary = hang_stream_unary
+    elif self.response_streaming:
+      if partial_hang:
+        self.unary_stream = hang_partial_unary_stream
+      else:
+        self.unary_stream = hang_unary_stream
+    else:
+      self.unary_unary = hang_unary_unary
+
+
+class GenericHandler(grpc.GenericRpcHandler):
+
+  def service(self, handler_call_details):
+    if handler_call_details.method == UNARY_UNARY:
+      return MethodHandler(False, False, False)
+    elif handler_call_details.method == UNARY_STREAM:
+      return MethodHandler(False, True, False)
+    elif handler_call_details.method == STREAM_UNARY:
+      return MethodHandler(True, False, False)
+    elif handler_call_details.method == STREAM_STREAM:
+      return MethodHandler(True, True, False)
+    elif handler_call_details.method == PARTIAL_UNARY_STREAM:
+      return MethodHandler(False, True, True)
+    elif handler_call_details.method == PARTIAL_STREAM_UNARY:
+      return MethodHandler(True, False, True)
+    elif handler_call_details.method == PARTIAL_STREAM_STREAM:
+      return MethodHandler(True, True, True)
+    else:
+      return None
+
+
+# Traditional executors will not exit until all their
+# current jobs complete.  Because we submit jobs that will
+# never finish, we don't want to block exit on these jobs.
+class DaemonPool(object):
+
+  def submit(self, fn, *args, **kwargs):
+    thread = threading.Thread(target=fn, args=args, kwargs=kwargs)
+    thread.daemon = True
+    thread.start()
+
+  def shutdown(self, wait=True):
+    pass
+
+
+def infinite_request_iterator():
+  while True:
+    yield REQUEST
+
+
+if __name__ == '__main__':
+  parser = argparse.ArgumentParser()
+  parser.add_argument('scenario', type=str)
+  parser.add_argument(
+      '--wait_for_interrupt', dest='wait_for_interrupt', action='store_true')
+  args = parser.parse_args()
+
+  if args.scenario == UNSTARTED_SERVER:
+    server = grpc.server((), DaemonPool())
+    if args.wait_for_interrupt:
+      time.sleep(WAIT_TIME)
+  elif args.scenario == RUNNING_SERVER:
+    server = grpc.server((), DaemonPool())
+    port = server.add_insecure_port('[::]:0')
+    server.start()
+    if args.wait_for_interrupt:
+      time.sleep(WAIT_TIME)
+  elif args.scenario == POLL_CONNECTIVITY_NO_SERVER:
+    channel = grpc.insecure_channel('localhost:12345')
+
+    def connectivity_callback(connectivity):
+      pass
+
+    channel.subscribe(connectivity_callback, try_to_connect=True)
+    if args.wait_for_interrupt:
+      time.sleep(WAIT_TIME)
+  elif args.scenario == POLL_CONNECTIVITY:
+    server = grpc.server((), DaemonPool())
+    port = server.add_insecure_port('[::]:0')
+    server.start()
+    channel = grpc.insecure_channel('localhost:%d' % port)
+
+    def connectivity_callback(connectivity):
+      pass
+
+    channel.subscribe(connectivity_callback, try_to_connect=True)
+    if args.wait_for_interrupt:
+      time.sleep(WAIT_TIME)
+
+  else:
+    handler = GenericHandler()
+    server = grpc.server((), DaemonPool())
+    port = server.add_insecure_port('[::]:0')
+    server.add_generic_rpc_handlers((handler,))
+    server.start()
+    channel = grpc.insecure_channel('localhost:%d' % port)
+
+    method = TEST_TO_METHOD[args.scenario]
+
+    if args.scenario == IN_FLIGHT_UNARY_UNARY_CALL:
+      multi_callable = channel.unary_unary(method)
+      future = multi_callable.future(REQUEST)
+      result, call = multi_callable.with_call(REQUEST)
+    elif (args.scenario == IN_FLIGHT_UNARY_STREAM_CALL or
+          args.scenario == IN_FLIGHT_PARTIAL_UNARY_STREAM_CALL):
+      multi_callable = channel.unary_stream(method)
+      response_iterator = multi_callable(REQUEST)
+      for response in response_iterator:
+        pass
+    elif (args.scenario == IN_FLIGHT_STREAM_UNARY_CALL or
+          args.scenario == IN_FLIGHT_PARTIAL_STREAM_UNARY_CALL):
+      multi_callable = channel.stream_unary(method)
+      future = multi_callable.future(infinite_request_iterator())
+      result, call = multi_callable.with_call(
+          [REQUEST] * test_constants.STREAM_LENGTH)
+    elif (args.scenario == IN_FLIGHT_STREAM_STREAM_CALL or
+          args.scenario == IN_FLIGHT_PARTIAL_STREAM_STREAM_CALL):
+      multi_callable = channel.stream_stream(method)
+      response_iterator = multi_callable(infinite_request_iterator())
+      for response in response_iterator:
+        pass
diff --git a/src/python/grpcio_tests/tests/unit/_exit_test.py b/src/python/grpcio_tests/tests/unit/_exit_test.py
new file mode 100644
index 0000000000..b0d6af73e5
--- /dev/null
+++ b/src/python/grpcio_tests/tests/unit/_exit_test.py
@@ -0,0 +1,185 @@
+# 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.
+
+"""Tests clean exit of server/client on Python Interpreter exit/sigint.
+
+The tests in this module spawn a subprocess for each test case, the
+test is considered successful if it doesn't hang/timeout.
+"""
+
+import atexit
+import os
+import signal
+import six
+import subprocess
+import sys
+import threading
+import time
+import unittest
+
+from tests.unit import _exit_scenarios
+
+SCENARIO_FILE = os.path.abspath(os.path.join(
+    os.path.dirname(os.path.realpath(__file__)), '_exit_scenarios.py'))
+INTERPRETER = sys.executable
+BASE_COMMAND = [INTERPRETER, SCENARIO_FILE]
+BASE_SIGTERM_COMMAND = BASE_COMMAND + ['--wait_for_interrupt']
+
+INIT_TIME = 1.0
+
+
+processes = []
+process_lock = threading.Lock()
+
+
+# Make sure we attempt to clean up any
+# processes we may have left running
+def cleanup_processes():
+  with process_lock:
+    for process in processes:
+      try:
+        process.kill()
+      except Exception:
+        pass
+atexit.register(cleanup_processes)
+
+
+def interrupt_and_wait(process):
+  with process_lock:
+    processes.append(process)
+  time.sleep(INIT_TIME)
+  os.kill(process.pid, signal.SIGINT)
+  process.wait()
+
+
+def wait(process):
+  with process_lock:
+    processes.append(process)
+  process.wait()
+
+
+class ExitTest(unittest.TestCase):
+
+  def test_unstarted_server(self):
+    process = subprocess.Popen(
+        BASE_COMMAND + [_exit_scenarios.UNSTARTED_SERVER],
+        stdout=sys.stdout, stderr=sys.stderr)
+    wait(process)
+
+  def test_unstarted_server_terminate(self):
+    process = subprocess.Popen(
+        BASE_SIGTERM_COMMAND + [_exit_scenarios.UNSTARTED_SERVER],
+        stdout=sys.stdout)
+    interrupt_and_wait(process)
+
+  def test_running_server(self):
+    process = subprocess.Popen(
+        BASE_COMMAND + [_exit_scenarios.RUNNING_SERVER],
+        stdout=sys.stdout, stderr=sys.stderr)
+    wait(process)
+
+  def test_running_server_terminate(self):
+    process = subprocess.Popen(
+        BASE_SIGTERM_COMMAND + [_exit_scenarios.RUNNING_SERVER],
+        stdout=sys.stdout, stderr=sys.stderr)
+    interrupt_and_wait(process)
+
+  def test_poll_connectivity_no_server(self):
+    process = subprocess.Popen(
+        BASE_COMMAND + [_exit_scenarios.POLL_CONNECTIVITY_NO_SERVER],
+        stdout=sys.stdout, stderr=sys.stderr)
+    wait(process)
+
+  def test_poll_connectivity_no_server_terminate(self):
+    process = subprocess.Popen(
+        BASE_SIGTERM_COMMAND + [_exit_scenarios.POLL_CONNECTIVITY_NO_SERVER],
+        stdout=sys.stdout, stderr=sys.stderr)
+    interrupt_and_wait(process)
+
+  def test_poll_connectivity(self):
+    process = subprocess.Popen(
+        BASE_COMMAND + [_exit_scenarios.POLL_CONNECTIVITY],
+        stdout=sys.stdout, stderr=sys.stderr)
+    wait(process)
+
+  def test_poll_connectivity_terminate(self):
+    process = subprocess.Popen(
+        BASE_SIGTERM_COMMAND + [_exit_scenarios.POLL_CONNECTIVITY],
+        stdout=sys.stdout, stderr=sys.stderr)
+    interrupt_and_wait(process)
+
+  def test_in_flight_unary_unary_call(self):
+    process = subprocess.Popen(
+        BASE_COMMAND + [_exit_scenarios.IN_FLIGHT_UNARY_UNARY_CALL],
+        stdout=sys.stdout, stderr=sys.stderr)
+    interrupt_and_wait(process)
+
+  @unittest.skipIf(six.PY2, 'https://github.com/grpc/grpc/issues/6999')
+  def test_in_flight_unary_stream_call(self):
+    process = subprocess.Popen(
+        BASE_COMMAND + [_exit_scenarios.IN_FLIGHT_UNARY_STREAM_CALL],
+        stdout=sys.stdout, stderr=sys.stderr)
+    interrupt_and_wait(process)
+
+  def test_in_flight_stream_unary_call(self):
+    process = subprocess.Popen(
+        BASE_COMMAND + [_exit_scenarios.IN_FLIGHT_STREAM_UNARY_CALL],
+        stdout=sys.stdout, stderr=sys.stderr)
+    interrupt_and_wait(process)
+
+  @unittest.skipIf(six.PY2, 'https://github.com/grpc/grpc/issues/6999')
+  def test_in_flight_stream_stream_call(self):
+    process = subprocess.Popen(
+        BASE_COMMAND + [_exit_scenarios.IN_FLIGHT_STREAM_STREAM_CALL],
+        stdout=sys.stdout, stderr=sys.stderr)
+    interrupt_and_wait(process)
+
+  @unittest.skipIf(six.PY2, 'https://github.com/grpc/grpc/issues/6999')
+  def test_in_flight_partial_unary_stream_call(self):
+    process = subprocess.Popen(
+        BASE_COMMAND + [_exit_scenarios.IN_FLIGHT_PARTIAL_UNARY_STREAM_CALL],
+        stdout=sys.stdout, stderr=sys.stderr)
+    interrupt_and_wait(process)
+
+  def test_in_flight_partial_stream_unary_call(self):
+    process = subprocess.Popen(
+        BASE_COMMAND + [_exit_scenarios.IN_FLIGHT_PARTIAL_STREAM_UNARY_CALL],
+        stdout=sys.stdout, stderr=sys.stderr)
+    interrupt_and_wait(process)
+
+  @unittest.skipIf(six.PY2, 'https://github.com/grpc/grpc/issues/6999')
+  def test_in_flight_partial_stream_stream_call(self):
+    process = subprocess.Popen(
+        BASE_COMMAND + [_exit_scenarios.IN_FLIGHT_PARTIAL_STREAM_STREAM_CALL],
+        stdout=sys.stdout, stderr=sys.stderr)
+    interrupt_and_wait(process)
+
+
+if __name__ == '__main__':
+  unittest.main(verbosity=2)
diff --git a/src/python/grpcio_tests/tests/unit/_from_grpc_import_star.py b/src/python/grpcio_tests/tests/unit/_from_grpc_import_star.py
new file mode 100644
index 0000000000..78d2fb7dc5
--- /dev/null
+++ b/src/python/grpcio_tests/tests/unit/_from_grpc_import_star.py
@@ -0,0 +1,38 @@
+# 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.
+
+_BEFORE_IMPORT = tuple(globals())
+
+from grpc import *
+
+_AFTER_IMPORT = tuple(globals())
+
+GRPC_ELEMENTS = tuple(
+    element for element in _AFTER_IMPORT
+    if element not in _BEFORE_IMPORT and element != '_BEFORE_IMPORT')
diff --git a/src/python/grpcio_tests/tests/unit/_junkdrawer/__init__.py b/src/python/grpcio_tests/tests/unit/_junkdrawer/__init__.py
new file mode 100644
index 0000000000..7086519106
--- /dev/null
+++ b/src/python/grpcio_tests/tests/unit/_junkdrawer/__init__.py
@@ -0,0 +1,30 @@
+# 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/_junkdrawer/math_pb2.py b/src/python/grpcio_tests/tests/unit/_junkdrawer/math_pb2.py
new file mode 100644
index 0000000000..20165955b4
--- /dev/null
+++ b/src/python/grpcio_tests/tests/unit/_junkdrawer/math_pb2.py
@@ -0,0 +1,266 @@
+# 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.
+
+# TODO(nathaniel): Remove this from source control after having made
+# generation from the math.proto source part of GRPC's build-and-test
+# process.
+
+# Generated by the protocol buffer compiler.  DO NOT EDIT!
+# source: math.proto
+
+import sys
+_b=sys.version_info[0]<3 and (lambda x:x) or (lambda x:x.encode('latin1'))
+from google.protobuf import descriptor as _descriptor
+from google.protobuf import message as _message
+from google.protobuf import reflection as _reflection
+from google.protobuf import symbol_database as _symbol_database
+from google.protobuf import descriptor_pb2
+# @@protoc_insertion_point(imports)
+
+_sym_db = _symbol_database.Default()
+
+
+
+
+DESCRIPTOR = _descriptor.FileDescriptor(
+  name='math.proto',
+  package='math',
+  serialized_pb=_b('\n\nmath.proto\x12\x04math\",\n\x07\x44ivArgs\x12\x10\n\x08\x64ividend\x18\x01 \x02(\x03\x12\x0f\n\x07\x64ivisor\x18\x02 \x02(\x03\"/\n\x08\x44ivReply\x12\x10\n\x08quotient\x18\x01 \x02(\x03\x12\x11\n\tremainder\x18\x02 \x02(\x03\"\x18\n\x07\x46ibArgs\x12\r\n\x05limit\x18\x01 \x01(\x03\"\x12\n\x03Num\x12\x0b\n\x03num\x18\x01 \x02(\x03\"\x19\n\x08\x46ibReply\x12\r\n\x05\x63ount\x18\x01 \x02(\x03\x32\xa4\x01\n\x04Math\x12&\n\x03\x44iv\x12\r.math.DivArgs\x1a\x0e.math.DivReply\"\x00\x12.\n\x07\x44ivMany\x12\r.math.DivArgs\x1a\x0e.math.DivReply\"\x00(\x01\x30\x01\x12#\n\x03\x46ib\x12\r.math.FibArgs\x1a\t.math.Num\"\x00\x30\x01\x12\x1f\n\x03Sum\x12\t.math.Num\x1a\t.math.Num\"\x00(\x01')
+)
+_sym_db.RegisterFileDescriptor(DESCRIPTOR)
+
+
+
+
+_DIVARGS = _descriptor.Descriptor(
+  name='DivArgs',
+  full_name='math.DivArgs',
+  filename=None,
+  file=DESCRIPTOR,
+  containing_type=None,
+  fields=[
+    _descriptor.FieldDescriptor(
+      name='dividend', full_name='math.DivArgs.dividend', index=0,
+      number=1, type=3, cpp_type=2, label=2,
+      has_default_value=False, default_value=0,
+      message_type=None, enum_type=None, containing_type=None,
+      is_extension=False, extension_scope=None,
+      options=None),
+    _descriptor.FieldDescriptor(
+      name='divisor', full_name='math.DivArgs.divisor', index=1,
+      number=2, type=3, cpp_type=2, label=2,
+      has_default_value=False, default_value=0,
+      message_type=None, enum_type=None, containing_type=None,
+      is_extension=False, extension_scope=None,
+      options=None),
+  ],
+  extensions=[
+  ],
+  nested_types=[],
+  enum_types=[
+  ],
+  options=None,
+  is_extendable=False,
+  extension_ranges=[],
+  oneofs=[
+  ],
+  serialized_start=20,
+  serialized_end=64,
+)
+
+
+_DIVREPLY = _descriptor.Descriptor(
+  name='DivReply',
+  full_name='math.DivReply',
+  filename=None,
+  file=DESCRIPTOR,
+  containing_type=None,
+  fields=[
+    _descriptor.FieldDescriptor(
+      name='quotient', full_name='math.DivReply.quotient', index=0,
+      number=1, type=3, cpp_type=2, label=2,
+      has_default_value=False, default_value=0,
+      message_type=None, enum_type=None, containing_type=None,
+      is_extension=False, extension_scope=None,
+      options=None),
+    _descriptor.FieldDescriptor(
+      name='remainder', full_name='math.DivReply.remainder', index=1,
+      number=2, type=3, cpp_type=2, label=2,
+      has_default_value=False, default_value=0,
+      message_type=None, enum_type=None, containing_type=None,
+      is_extension=False, extension_scope=None,
+      options=None),
+  ],
+  extensions=[
+  ],
+  nested_types=[],
+  enum_types=[
+  ],
+  options=None,
+  is_extendable=False,
+  extension_ranges=[],
+  oneofs=[
+  ],
+  serialized_start=66,
+  serialized_end=113,
+)
+
+
+_FIBARGS = _descriptor.Descriptor(
+  name='FibArgs',
+  full_name='math.FibArgs',
+  filename=None,
+  file=DESCRIPTOR,
+  containing_type=None,
+  fields=[
+    _descriptor.FieldDescriptor(
+      name='limit', full_name='math.FibArgs.limit', index=0,
+      number=1, type=3, cpp_type=2, label=1,
+      has_default_value=False, default_value=0,
+      message_type=None, enum_type=None, containing_type=None,
+      is_extension=False, extension_scope=None,
+      options=None),
+  ],
+  extensions=[
+  ],
+  nested_types=[],
+  enum_types=[
+  ],
+  options=None,
+  is_extendable=False,
+  extension_ranges=[],
+  oneofs=[
+  ],
+  serialized_start=115,
+  serialized_end=139,
+)
+
+
+_NUM = _descriptor.Descriptor(
+  name='Num',
+  full_name='math.Num',
+  filename=None,
+  file=DESCRIPTOR,
+  containing_type=None,
+  fields=[
+    _descriptor.FieldDescriptor(
+      name='num', full_name='math.Num.num', index=0,
+      number=1, type=3, cpp_type=2, label=2,
+      has_default_value=False, default_value=0,
+      message_type=None, enum_type=None, containing_type=None,
+      is_extension=False, extension_scope=None,
+      options=None),
+  ],
+  extensions=[
+  ],
+  nested_types=[],
+  enum_types=[
+  ],
+  options=None,
+  is_extendable=False,
+  extension_ranges=[],
+  oneofs=[
+  ],
+  serialized_start=141,
+  serialized_end=159,
+)
+
+
+_FIBREPLY = _descriptor.Descriptor(
+  name='FibReply',
+  full_name='math.FibReply',
+  filename=None,
+  file=DESCRIPTOR,
+  containing_type=None,
+  fields=[
+    _descriptor.FieldDescriptor(
+      name='count', full_name='math.FibReply.count', index=0,
+      number=1, type=3, cpp_type=2, label=2,
+      has_default_value=False, default_value=0,
+      message_type=None, enum_type=None, containing_type=None,
+      is_extension=False, extension_scope=None,
+      options=None),
+  ],
+  extensions=[
+  ],
+  nested_types=[],
+  enum_types=[
+  ],
+  options=None,
+  is_extendable=False,
+  extension_ranges=[],
+  oneofs=[
+  ],
+  serialized_start=161,
+  serialized_end=186,
+)
+
+DESCRIPTOR.message_types_by_name['DivArgs'] = _DIVARGS
+DESCRIPTOR.message_types_by_name['DivReply'] = _DIVREPLY
+DESCRIPTOR.message_types_by_name['FibArgs'] = _FIBARGS
+DESCRIPTOR.message_types_by_name['Num'] = _NUM
+DESCRIPTOR.message_types_by_name['FibReply'] = _FIBREPLY
+
+DivArgs = _reflection.GeneratedProtocolMessageType('DivArgs', (_message.Message,), dict(
+  DESCRIPTOR = _DIVARGS,
+  __module__ = 'math_pb2'
+  # @@protoc_insertion_point(class_scope:math.DivArgs)
+  ))
+_sym_db.RegisterMessage(DivArgs)
+
+DivReply = _reflection.GeneratedProtocolMessageType('DivReply', (_message.Message,), dict(
+  DESCRIPTOR = _DIVREPLY,
+  __module__ = 'math_pb2'
+  # @@protoc_insertion_point(class_scope:math.DivReply)
+  ))
+_sym_db.RegisterMessage(DivReply)
+
+FibArgs = _reflection.GeneratedProtocolMessageType('FibArgs', (_message.Message,), dict(
+  DESCRIPTOR = _FIBARGS,
+  __module__ = 'math_pb2'
+  # @@protoc_insertion_point(class_scope:math.FibArgs)
+  ))
+_sym_db.RegisterMessage(FibArgs)
+
+Num = _reflection.GeneratedProtocolMessageType('Num', (_message.Message,), dict(
+  DESCRIPTOR = _NUM,
+  __module__ = 'math_pb2'
+  # @@protoc_insertion_point(class_scope:math.Num)
+  ))
+_sym_db.RegisterMessage(Num)
+
+FibReply = _reflection.GeneratedProtocolMessageType('FibReply', (_message.Message,), dict(
+  DESCRIPTOR = _FIBREPLY,
+  __module__ = 'math_pb2'
+  # @@protoc_insertion_point(class_scope:math.FibReply)
+  ))
+_sym_db.RegisterMessage(FibReply)
+
+
+# @@protoc_insertion_point(module_scope)
diff --git a/src/python/grpcio_tests/tests/unit/_junkdrawer/stock_pb2.py b/src/python/grpcio_tests/tests/unit/_junkdrawer/stock_pb2.py
new file mode 100644
index 0000000000..eef18f82d6
--- /dev/null
+++ b/src/python/grpcio_tests/tests/unit/_junkdrawer/stock_pb2.py
@@ -0,0 +1,152 @@
+# 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.
+
+# TODO(nathaniel): Remove this from source control after having made
+# generation from the stock.proto source part of GRPC's build-and-test
+# process.
+
+# Generated by the protocol buffer compiler.  DO NOT EDIT!
+# source: stock.proto
+
+import sys
+_b=sys.version_info[0]<3 and (lambda x:x) or (lambda x:x.encode('latin1'))
+from google.protobuf import descriptor as _descriptor
+from google.protobuf import message as _message
+from google.protobuf import reflection as _reflection
+from google.protobuf import symbol_database as _symbol_database
+from google.protobuf import descriptor_pb2
+# @@protoc_insertion_point(imports)
+
+_sym_db = _symbol_database.Default()
+
+
+
+
+DESCRIPTOR = _descriptor.FileDescriptor(
+  name='stock.proto',
+  package='stock',
+  serialized_pb=_b('\n\x0bstock.proto\x12\x05stock\">\n\x0cStockRequest\x12\x0e\n\x06symbol\x18\x01 \x01(\t\x12\x1e\n\x13num_trades_to_watch\x18\x02 \x01(\x05:\x01\x30\"+\n\nStockReply\x12\r\n\x05price\x18\x01 \x01(\x02\x12\x0e\n\x06symbol\x18\x02 \x01(\t2\x96\x02\n\x05Stock\x12=\n\x11GetLastTradePrice\x12\x13.stock.StockRequest\x1a\x11.stock.StockReply\"\x00\x12I\n\x19GetLastTradePriceMultiple\x12\x13.stock.StockRequest\x1a\x11.stock.StockReply\"\x00(\x01\x30\x01\x12?\n\x11WatchFutureTrades\x12\x13.stock.StockRequest\x1a\x11.stock.StockReply\"\x00\x30\x01\x12\x42\n\x14GetHighestTradePrice\x12\x13.stock.StockRequest\x1a\x11.stock.StockReply\"\x00(\x01')
+)
+_sym_db.RegisterFileDescriptor(DESCRIPTOR)
+
+
+
+
+_STOCKREQUEST = _descriptor.Descriptor(
+  name='StockRequest',
+  full_name='stock.StockRequest',
+  filename=None,
+  file=DESCRIPTOR,
+  containing_type=None,
+  fields=[
+    _descriptor.FieldDescriptor(
+      name='symbol', full_name='stock.StockRequest.symbol', index=0,
+      number=1, type=9, cpp_type=9, label=1,
+      has_default_value=False, default_value=_b("").decode('utf-8'),
+      message_type=None, enum_type=None, containing_type=None,
+      is_extension=False, extension_scope=None,
+      options=None),
+    _descriptor.FieldDescriptor(
+      name='num_trades_to_watch', full_name='stock.StockRequest.num_trades_to_watch', index=1,
+      number=2, type=5, cpp_type=1, label=1,
+      has_default_value=True, default_value=0,
+      message_type=None, enum_type=None, containing_type=None,
+      is_extension=False, extension_scope=None,
+      options=None),
+  ],
+  extensions=[
+  ],
+  nested_types=[],
+  enum_types=[
+  ],
+  options=None,
+  is_extendable=False,
+  extension_ranges=[],
+  oneofs=[
+  ],
+  serialized_start=22,
+  serialized_end=84,
+)
+
+
+_STOCKREPLY = _descriptor.Descriptor(
+  name='StockReply',
+  full_name='stock.StockReply',
+  filename=None,
+  file=DESCRIPTOR,
+  containing_type=None,
+  fields=[
+    _descriptor.FieldDescriptor(
+      name='price', full_name='stock.StockReply.price', index=0,
+      number=1, type=2, cpp_type=6, label=1,
+      has_default_value=False, default_value=0,
+      message_type=None, enum_type=None, containing_type=None,
+      is_extension=False, extension_scope=None,
+      options=None),
+    _descriptor.FieldDescriptor(
+      name='symbol', full_name='stock.StockReply.symbol', index=1,
+      number=2, type=9, cpp_type=9, label=1,
+      has_default_value=False, default_value=_b("").decode('utf-8'),
+      message_type=None, enum_type=None, containing_type=None,
+      is_extension=False, extension_scope=None,
+      options=None),
+  ],
+  extensions=[
+  ],
+  nested_types=[],
+  enum_types=[
+  ],
+  options=None,
+  is_extendable=False,
+  extension_ranges=[],
+  oneofs=[
+  ],
+  serialized_start=86,
+  serialized_end=129,
+)
+
+DESCRIPTOR.message_types_by_name['StockRequest'] = _STOCKREQUEST
+DESCRIPTOR.message_types_by_name['StockReply'] = _STOCKREPLY
+
+StockRequest = _reflection.GeneratedProtocolMessageType('StockRequest', (_message.Message,), dict(
+  DESCRIPTOR = _STOCKREQUEST,
+  __module__ = 'stock_pb2'
+  # @@protoc_insertion_point(class_scope:stock.StockRequest)
+  ))
+_sym_db.RegisterMessage(StockRequest)
+
+StockReply = _reflection.GeneratedProtocolMessageType('StockReply', (_message.Message,), dict(
+  DESCRIPTOR = _STOCKREPLY,
+  __module__ = 'stock_pb2'
+  # @@protoc_insertion_point(class_scope:stock.StockReply)
+  ))
+_sym_db.RegisterMessage(StockReply)
+
+
+# @@protoc_insertion_point(module_scope)
diff --git a/src/python/grpcio_tests/tests/unit/_links/__init__.py b/src/python/grpcio_tests/tests/unit/_links/__init__.py
new file mode 100644
index 0000000000..7086519106
--- /dev/null
+++ b/src/python/grpcio_tests/tests/unit/_links/__init__.py
@@ -0,0 +1,30 @@
+# 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/_links/_proto_scenarios.py b/src/python/grpcio_tests/tests/unit/_links/_proto_scenarios.py
new file mode 100644
index 0000000000..50661085f9
--- /dev/null
+++ b/src/python/grpcio_tests/tests/unit/_links/_proto_scenarios.py
@@ -0,0 +1,262 @@
+# 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.
+
+"""Test scenarios using protocol buffers."""
+
+import abc
+import threading
+
+import six
+
+from tests.unit._junkdrawer import math_pb2
+from tests.unit.framework.common import test_constants
+
+
+class ProtoScenario(six.with_metaclass(abc.ABCMeta)):
+  """An RPC test scenario using protocol buffers."""
+
+  @abc.abstractmethod
+  def group_and_method(self):
+    """Access the test group and method.
+
+    Returns:
+      The test group and method as a pair.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def serialize_request(self, request):
+    """Serialize a request protocol buffer.
+
+    Args:
+      request: A request protocol buffer.
+
+    Returns:
+      The bytestring serialization of the given request protocol buffer.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def deserialize_request(self, request_bytestring):
+    """Deserialize a request protocol buffer.
+
+    Args:
+      request_bytestring: The bytestring serialization of a request protocol
+        buffer.
+
+    Returns:
+      The request protocol buffer deserialized from the given byte string.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def serialize_response(self, response):
+    """Serialize a response protocol buffer.
+
+    Args:
+      response: A response protocol buffer.
+
+    Returns:
+      The bytestring serialization of the given response protocol buffer.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def deserialize_response(self, response_bytestring):
+    """Deserialize a response protocol buffer.
+
+    Args:
+      response_bytestring: The bytestring serialization of a response protocol
+        buffer.
+
+    Returns:
+      The response protocol buffer deserialized from the given byte string.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def requests(self):
+    """Access the sequence of requests for this scenario.
+
+    Returns:
+      A sequence of request protocol buffers.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def response_for_request(self, request):
+    """Access the response for a particular request.
+
+    Args:
+      request: A request protocol buffer.
+
+    Returns:
+      The response protocol buffer appropriate for the given request.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def verify_requests(self, experimental_requests):
+    """Verify the requests transmitted through the system under test.
+
+    Args:
+      experimental_requests: The request protocol buffers transmitted through
+        the system under test.
+
+    Returns:
+      True if the requests satisfy this test scenario; False otherwise.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def verify_responses(self, experimental_responses):
+    """Verify the responses transmitted through the system under test.
+
+    Args:
+      experimental_responses: The response protocol buffers transmitted through
+        the system under test.
+
+    Returns:
+      True if the responses satisfy this test scenario; False otherwise.
+    """
+    raise NotImplementedError()
+
+
+class EmptyScenario(ProtoScenario):
+  """A scenario that transmits no protocol buffers in either direction."""
+
+  def group_and_method(self):
+    return 'math.Math', 'DivMany'
+
+  def serialize_request(self, request):
+    raise ValueError('This should not be necessary to call!')
+
+  def deserialize_request(self, request_bytestring):
+    raise ValueError('This should not be necessary to call!')
+
+  def serialize_response(self, response):
+    raise ValueError('This should not be necessary to call!')
+
+  def deserialize_response(self, response_bytestring):
+    raise ValueError('This should not be necessary to call!')
+
+  def requests(self):
+    return ()
+
+  def response_for_request(self, request):
+    raise ValueError('This should not be necessary to call!')
+
+  def verify_requests(self, experimental_requests):
+    return not experimental_requests
+
+  def verify_responses(self, experimental_responses):
+    return not experimental_responses
+
+
+class BidirectionallyUnaryScenario(ProtoScenario):
+  """A scenario that transmits no protocol buffers in either direction."""
+
+  _DIVIDEND = 59
+  _DIVISOR = 7
+  _QUOTIENT = 8
+  _REMAINDER = 3
+
+  _REQUEST = math_pb2.DivArgs(dividend=_DIVIDEND, divisor=_DIVISOR)
+  _RESPONSE = math_pb2.DivReply(quotient=_QUOTIENT, remainder=_REMAINDER)
+
+  def group_and_method(self):
+    return 'math.Math', 'Div'
+
+  def serialize_request(self, request):
+    return request.SerializeToString()
+
+  def deserialize_request(self, request_bytestring):
+    return math_pb2.DivArgs.FromString(request_bytestring)
+
+  def serialize_response(self, response):
+    return response.SerializeToString()
+
+  def deserialize_response(self, response_bytestring):
+    return math_pb2.DivReply.FromString(response_bytestring)
+
+  def requests(self):
+    return [self._REQUEST]
+
+  def response_for_request(self, request):
+    return self._RESPONSE
+
+  def verify_requests(self, experimental_requests):
+    return tuple(experimental_requests) == (self._REQUEST,)
+
+  def verify_responses(self, experimental_responses):
+    return tuple(experimental_responses) == (self._RESPONSE,)
+
+
+class BidirectionallyStreamingScenario(ProtoScenario):
+  """A scenario that transmits no protocol buffers in either direction."""
+
+  _REQUESTS = tuple(
+      math_pb2.DivArgs(dividend=59 + index, divisor=7 + index)
+      for index in range(test_constants.STREAM_LENGTH))
+
+  def __init__(self):
+    self._lock = threading.Lock()
+    self._responses = []
+
+  def group_and_method(self):
+    return 'math.Math', 'DivMany'
+
+  def serialize_request(self, request):
+    return request.SerializeToString()
+
+  def deserialize_request(self, request_bytestring):
+    return math_pb2.DivArgs.FromString(request_bytestring)
+
+  def serialize_response(self, response):
+    return response.SerializeToString()
+
+  def deserialize_response(self, response_bytestring):
+    return math_pb2.DivReply.FromString(response_bytestring)
+
+  def requests(self):
+    return self._REQUESTS
+
+  def response_for_request(self, request):
+    quotient, remainder = divmod(request.dividend, request.divisor)
+    response = math_pb2.DivReply(quotient=quotient, remainder=remainder)
+    with self._lock:
+      self._responses.append(response)
+    return response
+
+  def verify_requests(self, experimental_requests):
+    return tuple(experimental_requests) == self._REQUESTS
+
+  def verify_responses(self, experimental_responses):
+    with self._lock:
+      return tuple(experimental_responses) == tuple(self._responses)
diff --git a/src/python/grpcio_tests/tests/unit/_metadata_code_details_test.py b/src/python/grpcio_tests/tests/unit/_metadata_code_details_test.py
new file mode 100644
index 0000000000..0fd02d2a22
--- /dev/null
+++ b/src/python/grpcio_tests/tests/unit/_metadata_code_details_test.py
@@ -0,0 +1,523 @@
+# 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.
+
+"""Tests application-provided metadata, status code, and details."""
+
+import threading
+import unittest
+
+import grpc
+from grpc.framework.foundation import logging_pool
+
+from tests.unit import test_common
+from tests.unit.framework.common import test_constants
+from tests.unit.framework.common import test_control
+
+_SERIALIZED_REQUEST = b'\x46\x47\x48'
+_SERIALIZED_RESPONSE = b'\x49\x50\x51'
+
+_REQUEST_SERIALIZER = lambda unused_request: _SERIALIZED_REQUEST
+_REQUEST_DESERIALIZER = lambda unused_serialized_request: object()
+_RESPONSE_SERIALIZER = lambda unused_response: _SERIALIZED_RESPONSE
+_RESPONSE_DESERIALIZER = lambda unused_serialized_resopnse: object()
+
+_SERVICE = 'test.TestService'
+_UNARY_UNARY = 'UnaryUnary'
+_UNARY_STREAM = 'UnaryStream'
+_STREAM_UNARY = 'StreamUnary'
+_STREAM_STREAM = 'StreamStream'
+
+_CLIENT_METADATA = (
+    ('client-md-key', 'client-md-key'),
+    ('client-md-key-bin', b'\x00\x01')
+)
+
+_SERVER_INITIAL_METADATA = (
+    ('server-initial-md-key', 'server-initial-md-value'),
+    ('server-initial-md-key-bin', b'\x00\x02')
+)
+
+_SERVER_TRAILING_METADATA = (
+    ('server-trailing-md-key', 'server-trailing-md-value'),
+    ('server-trailing-md-key-bin', b'\x00\x03')
+)
+
+_NON_OK_CODE = grpc.StatusCode.NOT_FOUND
+_DETAILS = 'Test details!'
+
+
+class _Servicer(object):
+
+  def __init__(self):
+    self._lock = threading.Lock()
+    self._code = None
+    self._details = None
+    self._exception = False
+    self._return_none = False
+    self._received_client_metadata = None
+
+  def unary_unary(self, request, context):
+    with self._lock:
+      self._received_client_metadata = context.invocation_metadata()
+      context.send_initial_metadata(_SERVER_INITIAL_METADATA)
+      context.set_trailing_metadata(_SERVER_TRAILING_METADATA)
+      if self._code is not None:
+        context.set_code(self._code)
+      if self._details is not None:
+        context.set_details(self._details)
+      if self._exception:
+        raise test_control.Defect()
+      else:
+        return None if self._return_none else object()
+
+  def unary_stream(self, request, context):
+    with self._lock:
+      self._received_client_metadata = context.invocation_metadata()
+      context.send_initial_metadata(_SERVER_INITIAL_METADATA)
+      context.set_trailing_metadata(_SERVER_TRAILING_METADATA)
+      if self._code is not None:
+        context.set_code(self._code)
+      if self._details is not None:
+        context.set_details(self._details)
+      for _ in range(test_constants.STREAM_LENGTH // 2):
+        yield _SERIALIZED_RESPONSE
+      if self._exception:
+        raise test_control.Defect()
+
+  def stream_unary(self, request_iterator, context):
+    with self._lock:
+      self._received_client_metadata = context.invocation_metadata()
+      context.send_initial_metadata(_SERVER_INITIAL_METADATA)
+      context.set_trailing_metadata(_SERVER_TRAILING_METADATA)
+      if self._code is not None:
+        context.set_code(self._code)
+      if self._details is not None:
+        context.set_details(self._details)
+      # TODO(https://github.com/grpc/grpc/issues/6891): just ignore the
+      # request iterator.
+      for ignored_request in request_iterator:
+        pass
+      if self._exception:
+        raise test_control.Defect()
+      else:
+        return None if self._return_none else _SERIALIZED_RESPONSE
+
+  def stream_stream(self, request_iterator, context):
+    with self._lock:
+      self._received_client_metadata = context.invocation_metadata()
+      context.send_initial_metadata(_SERVER_INITIAL_METADATA)
+      context.set_trailing_metadata(_SERVER_TRAILING_METADATA)
+      if self._code is not None:
+        context.set_code(self._code)
+      if self._details is not None:
+        context.set_details(self._details)
+      # TODO(https://github.com/grpc/grpc/issues/6891): just ignore the
+      # request iterator.
+      for ignored_request in request_iterator:
+        pass
+      for _ in range(test_constants.STREAM_LENGTH // 3):
+        yield object()
+      if self._exception:
+        raise test_control.Defect()
+
+  def set_code(self, code):
+    with self._lock:
+      self._code = code
+
+  def set_details(self, details):
+    with self._lock:
+      self._details = details
+
+  def set_exception(self):
+    with self._lock:
+      self._exception = True
+
+  def set_return_none(self):
+    with self._lock:
+      self._return_none = True
+
+  def received_client_metadata(self):
+    with self._lock:
+      return self._received_client_metadata
+
+
+def _generic_handler(servicer):
+  method_handlers = {
+      _UNARY_UNARY: grpc.unary_unary_rpc_method_handler(
+          servicer.unary_unary, request_deserializer=_REQUEST_DESERIALIZER,
+          response_serializer=_RESPONSE_SERIALIZER),
+      _UNARY_STREAM: grpc.unary_stream_rpc_method_handler(
+          servicer.unary_stream),
+      _STREAM_UNARY: grpc.stream_unary_rpc_method_handler(
+          servicer.stream_unary),
+      _STREAM_STREAM: grpc.stream_stream_rpc_method_handler(
+          servicer.stream_stream, request_deserializer=_REQUEST_DESERIALIZER,
+          response_serializer=_RESPONSE_SERIALIZER),
+  }
+  return grpc.method_handlers_generic_handler(_SERVICE, method_handlers)
+
+
+class MetadataCodeDetailsTest(unittest.TestCase):
+
+  def setUp(self):
+    self._servicer = _Servicer()
+    self._server_pool = logging_pool.pool(test_constants.THREAD_CONCURRENCY)
+    self._server = grpc.server(
+        (_generic_handler(self._servicer),), self._server_pool)
+    port = self._server.add_insecure_port('[::]:0')
+    self._server.start()
+
+    channel = grpc.insecure_channel('localhost:{}'.format(port))
+    self._unary_unary = channel.unary_unary(
+        '/'.join(('', _SERVICE, _UNARY_UNARY,)),
+        request_serializer=_REQUEST_SERIALIZER,
+        response_deserializer=_RESPONSE_DESERIALIZER,)
+    self._unary_stream = channel.unary_stream(
+        '/'.join(('', _SERVICE, _UNARY_STREAM,)),)
+    self._stream_unary = channel.stream_unary(
+        '/'.join(('', _SERVICE, _STREAM_UNARY,)),)
+    self._stream_stream = channel.stream_stream(
+        '/'.join(('', _SERVICE, _STREAM_STREAM,)),
+        request_serializer=_REQUEST_SERIALIZER,
+        response_deserializer=_RESPONSE_DESERIALIZER,)
+
+
+  def testSuccessfulUnaryUnary(self):
+    self._servicer.set_details(_DETAILS)
+
+    unused_response, call = self._unary_unary.with_call(
+        object(), metadata=_CLIENT_METADATA)
+
+    self.assertTrue(
+        test_common.metadata_transmitted(
+            _CLIENT_METADATA, self._servicer.received_client_metadata()))
+    self.assertTrue(
+        test_common.metadata_transmitted(
+            _SERVER_INITIAL_METADATA, call.initial_metadata()))
+    self.assertTrue(
+        test_common.metadata_transmitted(
+            _SERVER_TRAILING_METADATA, call.trailing_metadata()))
+    self.assertIs(grpc.StatusCode.OK, call.code())
+    self.assertEqual(_DETAILS, call.details())
+
+  def testSuccessfulUnaryStream(self):
+    self._servicer.set_details(_DETAILS)
+
+    call = self._unary_stream(_SERIALIZED_REQUEST, metadata=_CLIENT_METADATA)
+    received_initial_metadata = call.initial_metadata()
+    for _ in call:
+      pass
+
+    self.assertTrue(
+        test_common.metadata_transmitted(
+            _CLIENT_METADATA, self._servicer.received_client_metadata()))
+    self.assertTrue(
+        test_common.metadata_transmitted(
+            _SERVER_INITIAL_METADATA, received_initial_metadata))
+    self.assertTrue(
+        test_common.metadata_transmitted(
+            _SERVER_TRAILING_METADATA, call.trailing_metadata()))
+    self.assertIs(grpc.StatusCode.OK, call.code())
+    self.assertEqual(_DETAILS, call.details())
+
+  def testSuccessfulStreamUnary(self):
+    self._servicer.set_details(_DETAILS)
+
+    unused_response, call = self._stream_unary.with_call(
+        iter([_SERIALIZED_REQUEST] * test_constants.STREAM_LENGTH),
+        metadata=_CLIENT_METADATA)
+
+    self.assertTrue(
+        test_common.metadata_transmitted(
+            _CLIENT_METADATA, self._servicer.received_client_metadata()))
+    self.assertTrue(
+        test_common.metadata_transmitted(
+            _SERVER_INITIAL_METADATA, call.initial_metadata()))
+    self.assertTrue(
+        test_common.metadata_transmitted(
+            _SERVER_TRAILING_METADATA, call.trailing_metadata()))
+    self.assertIs(grpc.StatusCode.OK, call.code())
+    self.assertEqual(_DETAILS, call.details())
+
+  def testSuccessfulStreamStream(self):
+    self._servicer.set_details(_DETAILS)
+
+    call = self._stream_stream(
+        iter([object()] * test_constants.STREAM_LENGTH),
+        metadata=_CLIENT_METADATA)
+    received_initial_metadata = call.initial_metadata()
+    for _ in call:
+      pass
+
+    self.assertTrue(
+        test_common.metadata_transmitted(
+            _CLIENT_METADATA, self._servicer.received_client_metadata()))
+    self.assertTrue(
+        test_common.metadata_transmitted(
+            _SERVER_INITIAL_METADATA, received_initial_metadata))
+    self.assertTrue(
+        test_common.metadata_transmitted(
+            _SERVER_TRAILING_METADATA, call.trailing_metadata()))
+    self.assertIs(grpc.StatusCode.OK, call.code())
+    self.assertEqual(_DETAILS, call.details())
+
+  def testCustomCodeUnaryUnary(self):
+    self._servicer.set_code(_NON_OK_CODE)
+    self._servicer.set_details(_DETAILS)
+
+    with self.assertRaises(grpc.RpcError) as exception_context:
+      self._unary_unary.with_call(object(), metadata=_CLIENT_METADATA)
+
+    self.assertTrue(
+        test_common.metadata_transmitted(
+            _CLIENT_METADATA, self._servicer.received_client_metadata()))
+    self.assertTrue(
+        test_common.metadata_transmitted(
+            _SERVER_INITIAL_METADATA,
+            exception_context.exception.initial_metadata()))
+    self.assertTrue(
+        test_common.metadata_transmitted(
+            _SERVER_TRAILING_METADATA,
+            exception_context.exception.trailing_metadata()))
+    self.assertIs(_NON_OK_CODE, exception_context.exception.code())
+    self.assertEqual(_DETAILS, exception_context.exception.details())
+
+  def testCustomCodeUnaryStream(self):
+    self._servicer.set_code(_NON_OK_CODE)
+    self._servicer.set_details(_DETAILS)
+
+    call = self._unary_stream(_SERIALIZED_REQUEST, metadata=_CLIENT_METADATA)
+    received_initial_metadata = call.initial_metadata()
+    with self.assertRaises(grpc.RpcError):
+      for _ in call:
+        pass
+
+    self.assertTrue(
+        test_common.metadata_transmitted(
+            _CLIENT_METADATA, self._servicer.received_client_metadata()))
+    self.assertTrue(
+        test_common.metadata_transmitted(
+            _SERVER_INITIAL_METADATA, received_initial_metadata))
+    self.assertTrue(
+        test_common.metadata_transmitted(
+            _SERVER_TRAILING_METADATA, call.trailing_metadata()))
+    self.assertIs(_NON_OK_CODE, call.code())
+    self.assertEqual(_DETAILS, call.details())
+
+  def testCustomCodeStreamUnary(self):
+    self._servicer.set_code(_NON_OK_CODE)
+    self._servicer.set_details(_DETAILS)
+
+    with self.assertRaises(grpc.RpcError) as exception_context:
+      self._stream_unary.with_call(
+          iter([_SERIALIZED_REQUEST] * test_constants.STREAM_LENGTH),
+          metadata=_CLIENT_METADATA)
+
+    self.assertTrue(
+        test_common.metadata_transmitted(
+          _CLIENT_METADATA, self._servicer.received_client_metadata()))
+    self.assertTrue(
+        test_common.metadata_transmitted(
+          _SERVER_INITIAL_METADATA,
+          exception_context.exception.initial_metadata()))
+    self.assertTrue(
+        test_common.metadata_transmitted(
+          _SERVER_TRAILING_METADATA,
+          exception_context.exception.trailing_metadata()))
+    self.assertIs(_NON_OK_CODE, exception_context.exception.code())
+    self.assertEqual(_DETAILS, exception_context.exception.details())
+
+  def testCustomCodeStreamStream(self):
+    self._servicer.set_code(_NON_OK_CODE)
+    self._servicer.set_details(_DETAILS)
+
+    call = self._stream_stream(
+        iter([object()] * test_constants.STREAM_LENGTH),
+        metadata=_CLIENT_METADATA)
+    received_initial_metadata = call.initial_metadata()
+    with self.assertRaises(grpc.RpcError) as exception_context:
+      for _ in call:
+        pass
+
+    self.assertTrue(
+        test_common.metadata_transmitted(
+          _CLIENT_METADATA, self._servicer.received_client_metadata()))
+    self.assertTrue(
+        test_common.metadata_transmitted(
+            _SERVER_INITIAL_METADATA, received_initial_metadata))
+    self.assertTrue(
+        test_common.metadata_transmitted(
+            _SERVER_TRAILING_METADATA,
+            exception_context.exception.trailing_metadata()))
+    self.assertIs(_NON_OK_CODE, exception_context.exception.code())
+    self.assertEqual(_DETAILS, exception_context.exception.details())
+
+  def testCustomCodeExceptionUnaryUnary(self):
+    self._servicer.set_code(_NON_OK_CODE)
+    self._servicer.set_details(_DETAILS)
+    self._servicer.set_exception()
+
+    with self.assertRaises(grpc.RpcError) as exception_context:
+     self._unary_unary.with_call(object(), metadata=_CLIENT_METADATA)
+
+    self.assertTrue(
+        test_common.metadata_transmitted(
+            _CLIENT_METADATA, self._servicer.received_client_metadata()))
+    self.assertTrue(
+        test_common.metadata_transmitted(
+            _SERVER_INITIAL_METADATA,
+            exception_context.exception.initial_metadata()))
+    self.assertTrue(
+        test_common.metadata_transmitted(
+            _SERVER_TRAILING_METADATA,
+            exception_context.exception.trailing_metadata()))
+    self.assertIs(_NON_OK_CODE, exception_context.exception.code())
+    self.assertEqual(_DETAILS, exception_context.exception.details())
+
+  def testCustomCodeExceptionUnaryStream(self):
+    self._servicer.set_code(_NON_OK_CODE)
+    self._servicer.set_details(_DETAILS)
+    self._servicer.set_exception()
+
+    call = self._unary_stream(_SERIALIZED_REQUEST, metadata=_CLIENT_METADATA)
+    received_initial_metadata = call.initial_metadata()
+    with self.assertRaises(grpc.RpcError):
+      for _ in call:
+        pass
+
+    self.assertTrue(
+        test_common.metadata_transmitted(
+            _CLIENT_METADATA, self._servicer.received_client_metadata()))
+    self.assertTrue(
+        test_common.metadata_transmitted(
+            _SERVER_INITIAL_METADATA, received_initial_metadata))
+    self.assertTrue(
+        test_common.metadata_transmitted(
+            _SERVER_TRAILING_METADATA, call.trailing_metadata()))
+    self.assertIs(_NON_OK_CODE, call.code())
+    self.assertEqual(_DETAILS, call.details())
+
+  def testCustomCodeExceptionStreamUnary(self):
+    self._servicer.set_code(_NON_OK_CODE)
+    self._servicer.set_details(_DETAILS)
+    self._servicer.set_exception()
+
+    with self.assertRaises(grpc.RpcError) as exception_context:
+      self._stream_unary.with_call(
+          iter([_SERIALIZED_REQUEST] * test_constants.STREAM_LENGTH),
+          metadata=_CLIENT_METADATA)
+
+    self.assertTrue(
+        test_common.metadata_transmitted(
+            _CLIENT_METADATA, self._servicer.received_client_metadata()))
+    self.assertTrue(
+        test_common.metadata_transmitted(
+            _SERVER_INITIAL_METADATA,
+            exception_context.exception.initial_metadata()))
+    self.assertTrue(
+        test_common.metadata_transmitted(
+            _SERVER_TRAILING_METADATA,
+            exception_context.exception.trailing_metadata()))
+    self.assertIs(_NON_OK_CODE, exception_context.exception.code())
+    self.assertEqual(_DETAILS, exception_context.exception.details())
+
+  def testCustomCodeExceptionStreamStream(self):
+    self._servicer.set_code(_NON_OK_CODE)
+    self._servicer.set_details(_DETAILS)
+    self._servicer.set_exception()
+
+    call = self._stream_stream(
+        iter([object()] * test_constants.STREAM_LENGTH),
+        metadata=_CLIENT_METADATA)
+    received_initial_metadata = call.initial_metadata()
+    with self.assertRaises(grpc.RpcError):
+      for _ in call:
+        pass
+
+    self.assertTrue(
+        test_common.metadata_transmitted(
+            _CLIENT_METADATA, self._servicer.received_client_metadata()))
+    self.assertTrue(
+        test_common.metadata_transmitted(
+            _SERVER_INITIAL_METADATA, received_initial_metadata))
+    self.assertTrue(
+        test_common.metadata_transmitted(
+            _SERVER_TRAILING_METADATA, call.trailing_metadata()))
+    self.assertIs(_NON_OK_CODE, call.code())
+    self.assertEqual(_DETAILS, call.details())
+
+  def testCustomCodeReturnNoneUnaryUnary(self):
+    self._servicer.set_code(_NON_OK_CODE)
+    self._servicer.set_details(_DETAILS)
+    self._servicer.set_return_none()
+
+    with self.assertRaises(grpc.RpcError) as exception_context:
+      self._unary_unary.with_call(object(), metadata=_CLIENT_METADATA)
+
+    self.assertTrue(
+        test_common.metadata_transmitted(
+            _CLIENT_METADATA, self._servicer.received_client_metadata()))
+    self.assertTrue(
+        test_common.metadata_transmitted(
+            _SERVER_INITIAL_METADATA,
+            exception_context.exception.initial_metadata()))
+    self.assertTrue(
+        test_common.metadata_transmitted(
+            _SERVER_TRAILING_METADATA,
+            exception_context.exception.trailing_metadata()))
+    self.assertIs(_NON_OK_CODE, exception_context.exception.code())
+    self.assertEqual(_DETAILS, exception_context.exception.details())
+
+  def testCustomCodeReturnNoneStreamUnary(self):
+    self._servicer.set_code(_NON_OK_CODE)
+    self._servicer.set_details(_DETAILS)
+    self._servicer.set_return_none()
+
+    with self.assertRaises(grpc.RpcError) as exception_context:
+      self._stream_unary.with_call(
+          iter([_SERIALIZED_REQUEST] * test_constants.STREAM_LENGTH),
+          metadata=_CLIENT_METADATA)
+
+    self.assertTrue(
+        test_common.metadata_transmitted(
+            _CLIENT_METADATA, self._servicer.received_client_metadata()))
+    self.assertTrue(
+        test_common.metadata_transmitted(
+            _SERVER_INITIAL_METADATA,
+            exception_context.exception.initial_metadata()))
+    self.assertTrue(
+        test_common.metadata_transmitted(
+            _SERVER_TRAILING_METADATA,
+            exception_context.exception.trailing_metadata()))
+    self.assertIs(_NON_OK_CODE, exception_context.exception.code())
+    self.assertEqual(_DETAILS, exception_context.exception.details())
+
+
+if __name__ == '__main__':
+  unittest.main(verbosity=2)
diff --git a/src/python/grpcio_tests/tests/unit/_metadata_test.py b/src/python/grpcio_tests/tests/unit/_metadata_test.py
new file mode 100644
index 0000000000..c637a28039
--- /dev/null
+++ b/src/python/grpcio_tests/tests/unit/_metadata_test.py
@@ -0,0 +1,216 @@
+# 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.
+"""Tests server and client side metadata API."""
+
+import unittest
+import weakref
+
+import grpc
+from grpc import _grpcio_metadata
+from grpc.framework.foundation import logging_pool
+
+from tests.unit import test_common
+from tests.unit.framework.common import test_constants
+
+_CHANNEL_ARGS = (('grpc.primary_user_agent', 'primary-agent'),
+                 ('grpc.secondary_user_agent', 'secondary-agent'))
+
+_REQUEST = b'\x00\x00\x00'
+_RESPONSE = b'\x00\x00\x00'
+
+_UNARY_UNARY = '/test/UnaryUnary'
+_UNARY_STREAM = '/test/UnaryStream'
+_STREAM_UNARY = '/test/StreamUnary'
+_STREAM_STREAM = '/test/StreamStream'
+
+_USER_AGENT = 'Python-gRPC-{}'.format(_grpcio_metadata.__version__)
+
+_CLIENT_METADATA = (
+    ('client-md-key', 'client-md-key'),
+    ('client-md-key-bin', b'\x00\x01')
+)
+
+_SERVER_INITIAL_METADATA = (
+    ('server-initial-md-key', 'server-initial-md-value'),
+    ('server-initial-md-key-bin', b'\x00\x02')
+)
+
+_SERVER_TRAILING_METADATA = (
+    ('server-trailing-md-key', 'server-trailing-md-value'),
+    ('server-trailing-md-key-bin', b'\x00\x03')
+)
+
+
+def user_agent(metadata):
+  for key, val in metadata:
+    if key == 'user-agent':
+      return val
+  raise KeyError('No user agent!')
+
+
+def validate_client_metadata(test, servicer_context):
+  test.assertTrue(test_common.metadata_transmitted(
+      _CLIENT_METADATA, servicer_context.invocation_metadata()))
+  test.assertTrue(user_agent(servicer_context.invocation_metadata())
+                  .startswith('primary-agent ' + _USER_AGENT))
+  test.assertTrue(user_agent(servicer_context.invocation_metadata())
+                  .endswith('secondary-agent'))
+
+
+def handle_unary_unary(test, request, servicer_context):
+  validate_client_metadata(test, servicer_context)
+  servicer_context.send_initial_metadata(_SERVER_INITIAL_METADATA)
+  servicer_context.set_trailing_metadata(_SERVER_TRAILING_METADATA)
+  return _RESPONSE
+
+
+def handle_unary_stream(test, request, servicer_context):
+  validate_client_metadata(test, servicer_context)
+  servicer_context.send_initial_metadata(_SERVER_INITIAL_METADATA)
+  servicer_context.set_trailing_metadata(_SERVER_TRAILING_METADATA)
+  for _ in range(test_constants.STREAM_LENGTH):
+    yield _RESPONSE
+
+
+def handle_stream_unary(test, request_iterator, servicer_context):
+  validate_client_metadata(test, servicer_context)
+  servicer_context.send_initial_metadata(_SERVER_INITIAL_METADATA)
+  servicer_context.set_trailing_metadata(_SERVER_TRAILING_METADATA)
+  # TODO(issue:#6891) We should be able to remove this loop
+  for request in request_iterator:
+    pass
+  return _RESPONSE
+
+
+def handle_stream_stream(test, request_iterator, servicer_context):
+  validate_client_metadata(test, servicer_context)
+  servicer_context.send_initial_metadata(_SERVER_INITIAL_METADATA)
+  servicer_context.set_trailing_metadata(_SERVER_TRAILING_METADATA)
+  # TODO(issue:#6891) We should be able to remove this loop,
+  # and replace with return; yield
+  for request in request_iterator:
+    yield _RESPONSE
+
+
+class _MethodHandler(grpc.RpcMethodHandler):
+
+  def __init__(self, test, request_streaming, response_streaming):
+    self.request_streaming = request_streaming
+    self.response_streaming = response_streaming
+    self.request_deserializer = None
+    self.response_serializer = None
+    self.unary_unary = None
+    self.unary_stream = None
+    self.stream_unary = None
+    self.stream_stream = None
+    if self.request_streaming and self.response_streaming:
+      self.stream_stream = lambda x, y: handle_stream_stream(test, x, y)
+    elif self.request_streaming:
+      self.stream_unary = lambda x, y: handle_stream_unary(test, x, y)
+    elif self.response_streaming:
+      self.unary_stream = lambda x, y: handle_unary_stream(test, x, y)
+    else:
+      self.unary_unary = lambda x, y: handle_unary_unary(test, x, y)
+
+
+class _GenericHandler(grpc.GenericRpcHandler):
+
+  def __init__(self, test):
+    self._test = test
+
+  def service(self, handler_call_details):
+    if handler_call_details.method == _UNARY_UNARY:
+      return _MethodHandler(self._test, False, False)
+    elif handler_call_details.method == _UNARY_STREAM:
+      return _MethodHandler(self._test, False, True)
+    elif handler_call_details.method == _STREAM_UNARY:
+      return _MethodHandler(self._test, True, False)
+    elif handler_call_details.method == _STREAM_STREAM:
+      return _MethodHandler(self._test, True, True)
+    else:
+      return None
+
+
+class MetadataTest(unittest.TestCase):
+
+  def setUp(self):
+    self._server_pool = logging_pool.pool(test_constants.THREAD_CONCURRENCY)
+    self._server = grpc.server((_GenericHandler(weakref.proxy(self)),),
+                               self._server_pool)
+    port = self._server.add_insecure_port('[::]:0')
+    self._server.start()
+    self._channel = grpc.insecure_channel('localhost:%d' % port,
+                                          options=_CHANNEL_ARGS)
+
+  def tearDown(self):
+    self._server.stop(0)
+
+  def testUnaryUnary(self):
+    multi_callable = self._channel.unary_unary(_UNARY_UNARY)
+    unused_response, call = multi_callable.with_call(
+        _REQUEST, metadata=_CLIENT_METADATA)
+    self.assertTrue(test_common.metadata_transmitted(
+        _SERVER_INITIAL_METADATA, call.initial_metadata()))
+    self.assertTrue(test_common.metadata_transmitted(
+        _SERVER_TRAILING_METADATA, call.trailing_metadata()))
+
+  def testUnaryStream(self):
+    multi_callable = self._channel.unary_stream(_UNARY_STREAM)
+    call = multi_callable(_REQUEST, metadata=_CLIENT_METADATA)
+    self.assertTrue(test_common.metadata_transmitted(
+        _SERVER_INITIAL_METADATA, call.initial_metadata()))
+    for _ in call:
+      pass
+    self.assertTrue(test_common.metadata_transmitted(
+        _SERVER_TRAILING_METADATA, call.trailing_metadata()))
+
+  def testStreamUnary(self):
+    multi_callable = self._channel.stream_unary(_STREAM_UNARY)
+    unused_response, call = multi_callable.with_call(
+        [_REQUEST] * test_constants.STREAM_LENGTH,
+        metadata=_CLIENT_METADATA)
+    self.assertTrue(test_common.metadata_transmitted(
+        _SERVER_INITIAL_METADATA, call.initial_metadata()))
+    self.assertTrue(test_common.metadata_transmitted(
+        _SERVER_TRAILING_METADATA, call.trailing_metadata()))
+
+  def testStreamStream(self):
+    multi_callable = self._channel.stream_stream(_STREAM_STREAM)
+    call = multi_callable([_REQUEST] * test_constants.STREAM_LENGTH,
+                          metadata=_CLIENT_METADATA)
+    self.assertTrue(test_common.metadata_transmitted(
+        _SERVER_INITIAL_METADATA, call.initial_metadata()))
+    for _ in call:
+      pass
+    self.assertTrue(test_common.metadata_transmitted(
+        _SERVER_TRAILING_METADATA, call.trailing_metadata()))
+
+
+if __name__ == '__main__':
+  unittest.main(verbosity=2)
diff --git a/src/python/grpcio_tests/tests/unit/_rpc_test.py b/src/python/grpcio_tests/tests/unit/_rpc_test.py
new file mode 100644
index 0000000000..c70d65a6df
--- /dev/null
+++ b/src/python/grpcio_tests/tests/unit/_rpc_test.py
@@ -0,0 +1,765 @@
+# 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 of RPCs made against gRPC Python's application-layer API."""
+
+import itertools
+import threading
+import unittest
+from concurrent import futures
+
+import grpc
+from grpc.framework.foundation import logging_pool
+
+from tests.unit.framework.common import test_constants
+from tests.unit.framework.common import test_control
+
+_SERIALIZE_REQUEST = lambda bytestring: bytestring * 2
+_DESERIALIZE_REQUEST = lambda bytestring: bytestring[len(bytestring) // 2:]
+_SERIALIZE_RESPONSE = lambda bytestring: bytestring * 3
+_DESERIALIZE_RESPONSE = lambda bytestring: bytestring[:len(bytestring) // 3]
+
+_UNARY_UNARY = '/test/UnaryUnary'
+_UNARY_STREAM = '/test/UnaryStream'
+_STREAM_UNARY = '/test/StreamUnary'
+_STREAM_STREAM = '/test/StreamStream'
+
+
+class _Callback(object):
+
+  def __init__(self):
+    self._condition = threading.Condition()
+    self._value = None
+    self._called = False
+
+  def __call__(self, value):
+    with self._condition:
+      self._value = value
+      self._called = True
+      self._condition.notify_all()
+
+  def value(self):
+    with self._condition:
+      while not self._called:
+        self._condition.wait()
+      return self._value
+
+
+class _Handler(object):
+
+  def __init__(self, control):
+    self._control = control
+
+  def handle_unary_unary(self, request, servicer_context):
+    self._control.control()
+    if servicer_context is not None:
+      servicer_context.set_trailing_metadata((('testkey', 'testvalue',),))
+    return request
+
+  def handle_unary_stream(self, request, servicer_context):
+    for _ in range(test_constants.STREAM_LENGTH):
+      self._control.control()
+      yield request
+    self._control.control()
+    if servicer_context is not None:
+      servicer_context.set_trailing_metadata((('testkey', 'testvalue',),))
+
+  def handle_stream_unary(self, request_iterator, servicer_context):
+    if servicer_context is not None:
+      servicer_context.invocation_metadata()
+    self._control.control()
+    response_elements = []
+    for request in request_iterator:
+      self._control.control()
+      response_elements.append(request)
+    self._control.control()
+    if servicer_context is not None:
+      servicer_context.set_trailing_metadata((('testkey', 'testvalue',),))
+    return b''.join(response_elements)
+
+  def handle_stream_stream(self, request_iterator, servicer_context):
+    self._control.control()
+    if servicer_context is not None:
+      servicer_context.set_trailing_metadata((('testkey', 'testvalue',),))
+    for request in request_iterator:
+      self._control.control()
+      yield request
+    self._control.control()
+
+
+class _MethodHandler(grpc.RpcMethodHandler):
+
+  def __init__(
+      self, request_streaming, response_streaming, request_deserializer,
+      response_serializer, unary_unary, unary_stream, stream_unary,
+      stream_stream):
+    self.request_streaming = request_streaming
+    self.response_streaming = response_streaming
+    self.request_deserializer = request_deserializer
+    self.response_serializer = response_serializer
+    self.unary_unary = unary_unary
+    self.unary_stream = unary_stream
+    self.stream_unary = stream_unary
+    self.stream_stream = stream_stream
+
+
+class _GenericHandler(grpc.GenericRpcHandler):
+
+  def __init__(self, handler):
+    self._handler = handler
+
+  def service(self, handler_call_details):
+    if handler_call_details.method == _UNARY_UNARY:
+      return _MethodHandler(
+          False, False, None, None, self._handler.handle_unary_unary, None,
+          None, None)
+    elif handler_call_details.method == _UNARY_STREAM:
+      return _MethodHandler(
+        False, True, _DESERIALIZE_REQUEST, _SERIALIZE_RESPONSE, None,
+        self._handler.handle_unary_stream, None, None)
+    elif handler_call_details.method == _STREAM_UNARY:
+      return _MethodHandler(
+          True, False, _DESERIALIZE_REQUEST, _SERIALIZE_RESPONSE, None, None,
+          self._handler.handle_stream_unary, None)
+    elif handler_call_details.method == _STREAM_STREAM:
+      return _MethodHandler(
+          True, True, None, None, None, None, None,
+          self._handler.handle_stream_stream)
+    else:
+      return None
+
+
+def _unary_unary_multi_callable(channel):
+  return channel.unary_unary(_UNARY_UNARY)
+
+
+def _unary_stream_multi_callable(channel):
+  return channel.unary_stream(
+      _UNARY_STREAM,
+      request_serializer=_SERIALIZE_REQUEST,
+      response_deserializer=_DESERIALIZE_RESPONSE)
+
+
+def _stream_unary_multi_callable(channel):
+  return channel.stream_unary(
+      _STREAM_UNARY,
+      request_serializer=_SERIALIZE_REQUEST,
+      response_deserializer=_DESERIALIZE_RESPONSE)
+
+
+def _stream_stream_multi_callable(channel):
+  return channel.stream_stream(_STREAM_STREAM)
+
+
+class RPCTest(unittest.TestCase):
+
+  def setUp(self):
+    self._control = test_control.PauseFailControl()
+    self._handler = _Handler(self._control)
+    self._server_pool = logging_pool.pool(test_constants.THREAD_CONCURRENCY)
+
+    self._server = grpc.server((), self._server_pool)
+    port = self._server.add_insecure_port('[::]:0')
+    self._server.add_generic_rpc_handlers((_GenericHandler(self._handler),))
+    self._server.start()
+
+    self._channel = grpc.insecure_channel('localhost:%d' % port)
+
+  def testUnrecognizedMethod(self):
+    request = b'abc'
+
+    with self.assertRaises(grpc.RpcError) as exception_context:
+      self._channel.unary_unary('NoSuchMethod')(request)
+
+    self.assertEqual(
+        grpc.StatusCode.UNIMPLEMENTED, exception_context.exception.code())
+
+  def testSuccessfulUnaryRequestBlockingUnaryResponse(self):
+    request = b'\x07\x08'
+    expected_response = self._handler.handle_unary_unary(request, None)
+
+    multi_callable = _unary_unary_multi_callable(self._channel)
+    response = multi_callable(
+        request, metadata=(
+            ('test', 'SuccessfulUnaryRequestBlockingUnaryResponse'),))
+
+    self.assertEqual(expected_response, response)
+
+  def testSuccessfulUnaryRequestBlockingUnaryResponseWithCall(self):
+    request = b'\x07\x08'
+    expected_response = self._handler.handle_unary_unary(request, None)
+
+    multi_callable = _unary_unary_multi_callable(self._channel)
+    response, call = multi_callable.with_call(
+        request, metadata=(
+            ('test', 'SuccessfulUnaryRequestBlockingUnaryResponseWithCall'),))
+
+    self.assertEqual(expected_response, response)
+    self.assertIs(grpc.StatusCode.OK, call.code())
+
+  def testSuccessfulUnaryRequestFutureUnaryResponse(self):
+    request = b'\x07\x08'
+    expected_response = self._handler.handle_unary_unary(request, None)
+
+    multi_callable = _unary_unary_multi_callable(self._channel)
+    response_future = multi_callable.future(
+        request, metadata=(
+            ('test', 'SuccessfulUnaryRequestFutureUnaryResponse'),))
+    response = response_future.result()
+
+    self.assertEqual(expected_response, response)
+
+  def testSuccessfulUnaryRequestStreamResponse(self):
+    request = b'\x37\x58'
+    expected_responses = tuple(self._handler.handle_unary_stream(request, None))
+
+    multi_callable = _unary_stream_multi_callable(self._channel)
+    response_iterator = multi_callable(
+        request,
+        metadata=(('test', 'SuccessfulUnaryRequestStreamResponse'),))
+    responses = tuple(response_iterator)
+
+    self.assertSequenceEqual(expected_responses, responses)
+
+  def testSuccessfulStreamRequestBlockingUnaryResponse(self):
+    requests = tuple(b'\x07\x08' for _ in range(test_constants.STREAM_LENGTH))
+    expected_response = self._handler.handle_stream_unary(iter(requests), None)
+    request_iterator = iter(requests)
+
+    multi_callable = _stream_unary_multi_callable(self._channel)
+    response = multi_callable(
+        request_iterator,
+        metadata=(('test', 'SuccessfulStreamRequestBlockingUnaryResponse'),))
+
+    self.assertEqual(expected_response, response)
+
+  def testSuccessfulStreamRequestBlockingUnaryResponseWithCall(self):
+    requests = tuple(b'\x07\x08' for _ in range(test_constants.STREAM_LENGTH))
+    expected_response = self._handler.handle_stream_unary(iter(requests), None)
+    request_iterator = iter(requests)
+
+    multi_callable = _stream_unary_multi_callable(self._channel)
+    response, call = multi_callable.with_call(
+        request_iterator,
+        metadata=(
+            ('test', 'SuccessfulStreamRequestBlockingUnaryResponseWithCall'),
+        ))
+
+    self.assertEqual(expected_response, response)
+    self.assertIs(grpc.StatusCode.OK, call.code())
+
+  def testSuccessfulStreamRequestFutureUnaryResponse(self):
+    requests = tuple(b'\x07\x08' for _ in range(test_constants.STREAM_LENGTH))
+    expected_response = self._handler.handle_stream_unary(iter(requests), None)
+    request_iterator = iter(requests)
+
+    multi_callable = _stream_unary_multi_callable(self._channel)
+    response_future = multi_callable.future(
+        request_iterator,
+        metadata=(
+            ('test', 'SuccessfulStreamRequestFutureUnaryResponse'),))
+    response = response_future.result()
+
+    self.assertEqual(expected_response, response)
+
+  def testSuccessfulStreamRequestStreamResponse(self):
+    requests = tuple(b'\x77\x58' for _ in range(test_constants.STREAM_LENGTH))
+    expected_responses = tuple(
+        self._handler.handle_stream_stream(iter(requests), None))
+    request_iterator = iter(requests)
+
+    multi_callable = _stream_stream_multi_callable(self._channel)
+    response_iterator = multi_callable(
+        request_iterator,
+        metadata=(('test', 'SuccessfulStreamRequestStreamResponse'),))
+    responses = tuple(response_iterator)
+
+    self.assertSequenceEqual(expected_responses, responses)
+
+  def testSequentialInvocations(self):
+    first_request = b'\x07\x08'
+    second_request = b'\x0809'
+    expected_first_response = self._handler.handle_unary_unary(
+        first_request, None)
+    expected_second_response = self._handler.handle_unary_unary(
+        second_request, None)
+
+    multi_callable = _unary_unary_multi_callable(self._channel)
+    first_response = multi_callable(
+        first_request, metadata=(('test', 'SequentialInvocations'),))
+    second_response = multi_callable(
+        second_request, metadata=(('test', 'SequentialInvocations'),))
+
+    self.assertEqual(expected_first_response, first_response)
+    self.assertEqual(expected_second_response, second_response)
+
+  def testConcurrentBlockingInvocations(self):
+    pool = logging_pool.pool(test_constants.THREAD_CONCURRENCY)
+    requests = tuple(b'\x07\x08' for _ in range(test_constants.STREAM_LENGTH))
+    expected_response = self._handler.handle_stream_unary(iter(requests), None)
+    expected_responses = [expected_response] * test_constants.THREAD_CONCURRENCY
+    response_futures = [None] * test_constants.THREAD_CONCURRENCY
+
+    multi_callable = _stream_unary_multi_callable(self._channel)
+    for index in range(test_constants.THREAD_CONCURRENCY):
+      request_iterator = iter(requests)
+      response_future = pool.submit(
+          multi_callable, request_iterator,
+          metadata=(('test', 'ConcurrentBlockingInvocations'),))
+      response_futures[index] = response_future
+    responses = tuple(
+        response_future.result() for response_future in response_futures)
+
+    pool.shutdown(wait=True)
+    self.assertSequenceEqual(expected_responses, responses)
+
+  def testConcurrentFutureInvocations(self):
+    requests = tuple(b'\x07\x08' for _ in range(test_constants.STREAM_LENGTH))
+    expected_response = self._handler.handle_stream_unary(iter(requests), None)
+    expected_responses = [expected_response] * test_constants.THREAD_CONCURRENCY
+    response_futures = [None] * test_constants.THREAD_CONCURRENCY
+
+    multi_callable = _stream_unary_multi_callable(self._channel)
+    for index in range(test_constants.THREAD_CONCURRENCY):
+      request_iterator = iter(requests)
+      response_future = multi_callable.future(
+          request_iterator,
+          metadata=(('test', 'ConcurrentFutureInvocations'),))
+      response_futures[index] = response_future
+    responses = tuple(
+        response_future.result() for response_future in response_futures)
+
+    self.assertSequenceEqual(expected_responses, responses)
+
+  def testWaitingForSomeButNotAllConcurrentFutureInvocations(self):
+    pool = logging_pool.pool(test_constants.THREAD_CONCURRENCY)
+    request = b'\x67\x68'
+    expected_response = self._handler.handle_unary_unary(request, None)
+    response_futures = [None] * test_constants.THREAD_CONCURRENCY
+    lock = threading.Lock()
+    test_is_running_cell = [True]
+    def wrap_future(future):
+      def wrap():
+        try:
+          return future.result()
+        except grpc.RpcError:
+          with lock:
+            if test_is_running_cell[0]:
+              raise
+          return None
+      return wrap
+
+    multi_callable = _unary_unary_multi_callable(self._channel)
+    for index in range(test_constants.THREAD_CONCURRENCY):
+      inner_response_future = multi_callable.future(
+          request,
+          metadata=(
+              ('test',
+               'WaitingForSomeButNotAllConcurrentFutureInvocations'),))
+      outer_response_future = pool.submit(wrap_future(inner_response_future))
+      response_futures[index] = outer_response_future
+
+    some_completed_response_futures_iterator = itertools.islice(
+        futures.as_completed(response_futures),
+        test_constants.THREAD_CONCURRENCY // 2)
+    for response_future in some_completed_response_futures_iterator:
+      self.assertEqual(expected_response, response_future.result())
+    with lock:
+      test_is_running_cell[0] = False
+
+  def testConsumingOneStreamResponseUnaryRequest(self):
+    request = b'\x57\x38'
+
+    multi_callable = _unary_stream_multi_callable(self._channel)
+    response_iterator = multi_callable(
+        request,
+        metadata=(
+            ('test', 'ConsumingOneStreamResponseUnaryRequest'),))
+    next(response_iterator)
+
+  def testConsumingSomeButNotAllStreamResponsesUnaryRequest(self):
+    request = b'\x57\x38'
+
+    multi_callable = _unary_stream_multi_callable(self._channel)
+    response_iterator = multi_callable(
+        request,
+        metadata=(
+            ('test', 'ConsumingSomeButNotAllStreamResponsesUnaryRequest'),))
+    for _ in range(test_constants.STREAM_LENGTH // 2):
+      next(response_iterator)
+
+  def testConsumingSomeButNotAllStreamResponsesStreamRequest(self):
+    requests = tuple(b'\x67\x88' for _ in range(test_constants.STREAM_LENGTH))
+    request_iterator = iter(requests)
+
+    multi_callable = _stream_stream_multi_callable(self._channel)
+    response_iterator = multi_callable(
+        request_iterator,
+        metadata=(
+            ('test', 'ConsumingSomeButNotAllStreamResponsesStreamRequest'),))
+    for _ in range(test_constants.STREAM_LENGTH // 2):
+      next(response_iterator)
+
+  def testConsumingTooManyStreamResponsesStreamRequest(self):
+    requests = tuple(b'\x67\x88' for _ in range(test_constants.STREAM_LENGTH))
+    request_iterator = iter(requests)
+
+    multi_callable = _stream_stream_multi_callable(self._channel)
+    response_iterator = multi_callable(
+        request_iterator,
+        metadata=(
+            ('test', 'ConsumingTooManyStreamResponsesStreamRequest'),))
+    for _ in range(test_constants.STREAM_LENGTH):
+      next(response_iterator)
+    for _ in range(test_constants.STREAM_LENGTH):
+      with self.assertRaises(StopIteration):
+        next(response_iterator)
+
+    self.assertIsNotNone(response_iterator.initial_metadata())
+    self.assertIs(grpc.StatusCode.OK, response_iterator.code())
+    self.assertIsNotNone(response_iterator.details())
+    self.assertIsNotNone(response_iterator.trailing_metadata())
+
+  def testCancelledUnaryRequestUnaryResponse(self):
+    request = b'\x07\x17'
+
+    multi_callable = _unary_unary_multi_callable(self._channel)
+    with self._control.pause():
+      response_future = multi_callable.future(
+          request,
+          metadata=(('test', 'CancelledUnaryRequestUnaryResponse'),))
+      response_future.cancel()
+
+    self.assertTrue(response_future.cancelled())
+    with self.assertRaises(grpc.FutureCancelledError):
+      response_future.result()
+    self.assertIs(grpc.StatusCode.CANCELLED, response_future.code())
+
+  def testCancelledUnaryRequestStreamResponse(self):
+    request = b'\x07\x19'
+
+    multi_callable = _unary_stream_multi_callable(self._channel)
+    with self._control.pause():
+      response_iterator = multi_callable(
+          request,
+          metadata=(('test', 'CancelledUnaryRequestStreamResponse'),))
+      self._control.block_until_paused()
+      response_iterator.cancel()
+
+    with self.assertRaises(grpc.RpcError) as exception_context:
+      next(response_iterator)
+    self.assertIs(grpc.StatusCode.CANCELLED, exception_context.exception.code())
+    self.assertIsNotNone(response_iterator.initial_metadata())
+    self.assertIs(grpc.StatusCode.CANCELLED, response_iterator.code())
+    self.assertIsNotNone(response_iterator.details())
+    self.assertIsNotNone(response_iterator.trailing_metadata())
+
+  def testCancelledStreamRequestUnaryResponse(self):
+    requests = tuple(b'\x07\x08' for _ in range(test_constants.STREAM_LENGTH))
+    request_iterator = iter(requests)
+
+    multi_callable = _stream_unary_multi_callable(self._channel)
+    with self._control.pause():
+      response_future = multi_callable.future(
+          request_iterator,
+          metadata=(('test', 'CancelledStreamRequestUnaryResponse'),))
+      self._control.block_until_paused()
+      response_future.cancel()
+
+    self.assertTrue(response_future.cancelled())
+    with self.assertRaises(grpc.FutureCancelledError):
+      response_future.result()
+    self.assertIsNotNone(response_future.initial_metadata())
+    self.assertIs(grpc.StatusCode.CANCELLED, response_future.code())
+    self.assertIsNotNone(response_future.details())
+    self.assertIsNotNone(response_future.trailing_metadata())
+
+  def testCancelledStreamRequestStreamResponse(self):
+    requests = tuple(b'\x07\x08' for _ in range(test_constants.STREAM_LENGTH))
+    request_iterator = iter(requests)
+
+    multi_callable = _stream_stream_multi_callable(self._channel)
+    with self._control.pause():
+      response_iterator = multi_callable(
+          request_iterator,
+          metadata=(('test', 'CancelledStreamRequestStreamResponse'),))
+      response_iterator.cancel()
+
+    with self.assertRaises(grpc.RpcError):
+      next(response_iterator)
+    self.assertIsNotNone(response_iterator.initial_metadata())
+    self.assertIs(grpc.StatusCode.CANCELLED, response_iterator.code())
+    self.assertIsNotNone(response_iterator.details())
+    self.assertIsNotNone(response_iterator.trailing_metadata())
+
+  def testExpiredUnaryRequestBlockingUnaryResponse(self):
+    request = b'\x07\x17'
+
+    multi_callable = _unary_unary_multi_callable(self._channel)
+    with self._control.pause():
+      with self.assertRaises(grpc.RpcError) as exception_context:
+        multi_callable.with_call(
+            request, timeout=test_constants.SHORT_TIMEOUT,
+            metadata=(('test', 'ExpiredUnaryRequestBlockingUnaryResponse'),))
+
+    self.assertIsNotNone(exception_context.exception.initial_metadata())
+    self.assertIs(
+        grpc.StatusCode.DEADLINE_EXCEEDED, exception_context.exception.code())
+    self.assertIsNotNone(exception_context.exception.details())
+    self.assertIsNotNone(exception_context.exception.trailing_metadata())
+
+  def testExpiredUnaryRequestFutureUnaryResponse(self):
+    request = b'\x07\x17'
+    callback = _Callback()
+
+    multi_callable = _unary_unary_multi_callable(self._channel)
+    with self._control.pause():
+      response_future = multi_callable.future(
+          request, timeout=test_constants.SHORT_TIMEOUT,
+          metadata=(('test', 'ExpiredUnaryRequestFutureUnaryResponse'),))
+      response_future.add_done_callback(callback)
+      value_passed_to_callback = callback.value()
+
+    self.assertIs(response_future, value_passed_to_callback)
+    self.assertIsNotNone(response_future.initial_metadata())
+    self.assertIs(grpc.StatusCode.DEADLINE_EXCEEDED, response_future.code())
+    self.assertIsNotNone(response_future.details())
+    self.assertIsNotNone(response_future.trailing_metadata())
+    with self.assertRaises(grpc.RpcError) as exception_context:
+      response_future.result()
+    self.assertIs(
+        grpc.StatusCode.DEADLINE_EXCEEDED, exception_context.exception.code())
+    self.assertIsInstance(response_future.exception(), grpc.RpcError)
+    self.assertIs(
+        grpc.StatusCode.DEADLINE_EXCEEDED, response_future.exception().code())
+
+  def testExpiredUnaryRequestStreamResponse(self):
+    request = b'\x07\x19'
+
+    multi_callable = _unary_stream_multi_callable(self._channel)
+    with self._control.pause():
+      with self.assertRaises(grpc.RpcError) as exception_context:
+        response_iterator = multi_callable(
+            request, timeout=test_constants.SHORT_TIMEOUT,
+            metadata=(('test', 'ExpiredUnaryRequestStreamResponse'),))
+        next(response_iterator)
+
+    self.assertIs(
+        grpc.StatusCode.DEADLINE_EXCEEDED, exception_context.exception.code())
+    self.assertIs(grpc.StatusCode.DEADLINE_EXCEEDED, response_iterator.code())
+
+  def testExpiredStreamRequestBlockingUnaryResponse(self):
+    requests = tuple(b'\x07\x08' for _ in range(test_constants.STREAM_LENGTH))
+    request_iterator = iter(requests)
+
+    multi_callable = _stream_unary_multi_callable(self._channel)
+    with self._control.pause():
+      with self.assertRaises(grpc.RpcError) as exception_context:
+        multi_callable(
+            request_iterator, timeout=test_constants.SHORT_TIMEOUT,
+            metadata=(('test', 'ExpiredStreamRequestBlockingUnaryResponse'),))
+
+    self.assertIsNotNone(exception_context.exception.initial_metadata())
+    self.assertIs(
+        grpc.StatusCode.DEADLINE_EXCEEDED, exception_context.exception.code())
+    self.assertIsNotNone(exception_context.exception.details())
+    self.assertIsNotNone(exception_context.exception.trailing_metadata())
+
+  def testExpiredStreamRequestFutureUnaryResponse(self):
+    requests = tuple(b'\x07\x18' for _ in range(test_constants.STREAM_LENGTH))
+    request_iterator = iter(requests)
+    callback = _Callback()
+
+    multi_callable = _stream_unary_multi_callable(self._channel)
+    with self._control.pause():
+      response_future = multi_callable.future(
+          request_iterator, timeout=test_constants.SHORT_TIMEOUT,
+          metadata=(('test', 'ExpiredStreamRequestFutureUnaryResponse'),))
+      response_future.add_done_callback(callback)
+      value_passed_to_callback = callback.value()
+
+    with self.assertRaises(grpc.RpcError) as exception_context:
+      response_future.result()
+    self.assertIs(grpc.StatusCode.DEADLINE_EXCEEDED, response_future.code())
+    self.assertIs(
+        grpc.StatusCode.DEADLINE_EXCEEDED, exception_context.exception.code())
+    self.assertIsInstance(response_future.exception(), grpc.RpcError)
+    self.assertIs(response_future, value_passed_to_callback)
+    self.assertIsNotNone(response_future.initial_metadata())
+    self.assertIs(grpc.StatusCode.DEADLINE_EXCEEDED, response_future.code())
+    self.assertIsNotNone(response_future.details())
+    self.assertIsNotNone(response_future.trailing_metadata())
+
+  def testExpiredStreamRequestStreamResponse(self):
+    requests = tuple(b'\x67\x18' for _ in range(test_constants.STREAM_LENGTH))
+    request_iterator = iter(requests)
+
+    multi_callable = _stream_stream_multi_callable(self._channel)
+    with self._control.pause():
+      with self.assertRaises(grpc.RpcError) as exception_context:
+        response_iterator = multi_callable(
+            request_iterator, timeout=test_constants.SHORT_TIMEOUT,
+            metadata=(('test', 'ExpiredStreamRequestStreamResponse'),))
+        next(response_iterator)
+
+    self.assertIs(
+        grpc.StatusCode.DEADLINE_EXCEEDED, exception_context.exception.code())
+    self.assertIs(grpc.StatusCode.DEADLINE_EXCEEDED, response_iterator.code())
+
+  def testFailedUnaryRequestBlockingUnaryResponse(self):
+    request = b'\x37\x17'
+
+    multi_callable = _unary_unary_multi_callable(self._channel)
+    with self._control.fail():
+      with self.assertRaises(grpc.RpcError) as exception_context:
+        multi_callable.with_call(
+            request,
+            metadata=(('test', 'FailedUnaryRequestBlockingUnaryResponse'),))
+
+    self.assertIs(grpc.StatusCode.UNKNOWN, exception_context.exception.code())
+
+  def testFailedUnaryRequestFutureUnaryResponse(self):
+    request = b'\x37\x17'
+    callback = _Callback()
+
+    multi_callable = _unary_unary_multi_callable(self._channel)
+    with self._control.fail():
+      response_future = multi_callable.future(
+          request,
+          metadata=(('test', 'FailedUnaryRequestFutureUnaryResponse'),))
+      response_future.add_done_callback(callback)
+      value_passed_to_callback = callback.value()
+
+    with self.assertRaises(grpc.RpcError) as exception_context:
+      response_future.result()
+    self.assertIs(
+        grpc.StatusCode.UNKNOWN, exception_context.exception.code())
+    self.assertIsInstance(response_future.exception(), grpc.RpcError)
+    self.assertIs(grpc.StatusCode.UNKNOWN, response_future.exception().code())
+    self.assertIs(response_future, value_passed_to_callback)
+
+  def testFailedUnaryRequestStreamResponse(self):
+    request = b'\x37\x17'
+
+    multi_callable = _unary_stream_multi_callable(self._channel)
+    with self.assertRaises(grpc.RpcError) as exception_context:
+      with self._control.fail():
+        response_iterator = multi_callable(
+            request,
+            metadata=(('test', 'FailedUnaryRequestStreamResponse'),))
+        next(response_iterator)
+
+    self.assertIs(grpc.StatusCode.UNKNOWN, exception_context.exception.code())
+
+  def testFailedStreamRequestBlockingUnaryResponse(self):
+    requests = tuple(b'\x47\x58' for _ in range(test_constants.STREAM_LENGTH))
+    request_iterator = iter(requests)
+
+    multi_callable = _stream_unary_multi_callable(self._channel)
+    with self._control.fail():
+      with self.assertRaises(grpc.RpcError) as exception_context:
+        multi_callable(
+            request_iterator,
+            metadata=(('test', 'FailedStreamRequestBlockingUnaryResponse'),))
+
+    self.assertIs(grpc.StatusCode.UNKNOWN, exception_context.exception.code())
+
+  def testFailedStreamRequestFutureUnaryResponse(self):
+    requests = tuple(b'\x07\x18' for _ in range(test_constants.STREAM_LENGTH))
+    request_iterator = iter(requests)
+    callback = _Callback()
+
+    multi_callable = _stream_unary_multi_callable(self._channel)
+    with self._control.fail():
+      response_future = multi_callable.future(
+          request_iterator,
+          metadata=(('test', 'FailedStreamRequestFutureUnaryResponse'),))
+      response_future.add_done_callback(callback)
+      value_passed_to_callback = callback.value()
+
+    with self.assertRaises(grpc.RpcError) as exception_context:
+      response_future.result()
+    self.assertIs(grpc.StatusCode.UNKNOWN, response_future.code())
+    self.assertIs(
+        grpc.StatusCode.UNKNOWN, exception_context.exception.code())
+    self.assertIsInstance(response_future.exception(), grpc.RpcError)
+    self.assertIs(response_future, value_passed_to_callback)
+
+  def testFailedStreamRequestStreamResponse(self):
+    requests = tuple(b'\x67\x88' for _ in range(test_constants.STREAM_LENGTH))
+    request_iterator = iter(requests)
+
+    multi_callable = _stream_stream_multi_callable(self._channel)
+    with self._control.fail():
+      with self.assertRaises(grpc.RpcError) as exception_context:
+        response_iterator = multi_callable(
+            request_iterator,
+            metadata=(('test', 'FailedStreamRequestStreamResponse'),))
+        tuple(response_iterator)
+
+    self.assertIs(grpc.StatusCode.UNKNOWN, exception_context.exception.code())
+    self.assertIs(grpc.StatusCode.UNKNOWN, response_iterator.code())
+
+  def testIgnoredUnaryRequestFutureUnaryResponse(self):
+    request = b'\x37\x17'
+
+    multi_callable = _unary_unary_multi_callable(self._channel)
+    multi_callable.future(
+        request,
+        metadata=(('test', 'IgnoredUnaryRequestFutureUnaryResponse'),))
+
+  def testIgnoredUnaryRequestStreamResponse(self):
+    request = b'\x37\x17'
+
+    multi_callable = _unary_stream_multi_callable(self._channel)
+    multi_callable(
+        request,
+        metadata=(('test', 'IgnoredUnaryRequestStreamResponse'),))
+
+  def testIgnoredStreamRequestFutureUnaryResponse(self):
+    requests = tuple(b'\x07\x18' for _ in range(test_constants.STREAM_LENGTH))
+    request_iterator = iter(requests)
+
+    multi_callable = _stream_unary_multi_callable(self._channel)
+    multi_callable.future(
+        request_iterator,
+        metadata=(('test', 'IgnoredStreamRequestFutureUnaryResponse'),))
+
+  def testIgnoredStreamRequestStreamResponse(self):
+    requests = tuple(b'\x67\x88' for _ in range(test_constants.STREAM_LENGTH))
+    request_iterator = iter(requests)
+
+    multi_callable = _stream_stream_multi_callable(self._channel)
+    multi_callable(
+        request_iterator,
+        metadata=(('test', 'IgnoredStreamRequestStreamResponse'),))
+
+
+if __name__ == '__main__':
+  unittest.main(verbosity=2)
diff --git a/src/python/grpcio_tests/tests/unit/_sanity/__init__.py b/src/python/grpcio_tests/tests/unit/_sanity/__init__.py
new file mode 100644
index 0000000000..2f88fa0412
--- /dev/null
+++ b/src/python/grpcio_tests/tests/unit/_sanity/__init__.py
@@ -0,0 +1,30 @@
+# 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.
+
+
diff --git a/src/python/grpcio_tests/tests/unit/_sanity/_sanity_test.py b/src/python/grpcio_tests/tests/unit/_sanity/_sanity_test.py
new file mode 100644
index 0000000000..e9fdf217ae
--- /dev/null
+++ b/src/python/grpcio_tests/tests/unit/_sanity/_sanity_test.py
@@ -0,0 +1,58 @@
+# 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 json
+import unittest
+
+import pkg_resources
+import six
+
+import tests
+
+
+class Sanity(unittest.TestCase):
+
+  def testTestsJsonUpToDate(self):
+    """Autodiscovers all test suites and checks that tests.json is up to date"""
+    loader = tests.Loader()
+    loader.loadTestsFromNames(['tests'])
+    test_suite_names = [
+        test_case_class.id().rsplit('.', 1)[0]
+        for test_case_class in tests._loader.iterate_suite_cases(loader.suite)]
+    test_suite_names = sorted(set(test_suite_names))
+
+    tests_json_string = pkg_resources.resource_string('tests', 'tests.json')
+    if six.PY3:
+      tests_json_string = tests_json_string.decode()
+    tests_json = json.loads(tests_json_string)
+    self.assertListEqual(test_suite_names, tests_json)
+
+
+if __name__ == '__main__':
+  unittest.main(verbosity=2)
diff --git a/src/python/grpcio_tests/tests/unit/_thread_cleanup_test.py b/src/python/grpcio_tests/tests/unit/_thread_cleanup_test.py
new file mode 100644
index 0000000000..3e4f317edc
--- /dev/null
+++ b/src/python/grpcio_tests/tests/unit/_thread_cleanup_test.py
@@ -0,0 +1,117 @@
+# 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.
+"""Tests for CleanupThread."""
+
+import threading
+import time
+import unittest
+
+from grpc import _common
+
+_SHORT_TIME = 0.5
+_LONG_TIME = 2.0
+_EPSILON = 0.1
+
+
+def cleanup(timeout):
+  if timeout is not None:
+    time.sleep(timeout)
+  else:
+    time.sleep(_LONG_TIME)
+
+
+def slow_cleanup(timeout):
+  # Don't respect timeout
+  time.sleep(_LONG_TIME)
+
+
+class CleanupThreadTest(unittest.TestCase):
+
+  def testTargetInvocation(self):
+    event = threading.Event()
+    def target(arg1, arg2, arg3=None):
+      self.assertEqual('arg1', arg1)
+      self.assertEqual('arg2', arg2)
+      self.assertEqual('arg3', arg3)
+      event.set()
+
+    cleanup_thread = _common.CleanupThread(behavior=lambda x: None,
+                              target=target, name='test-name',
+                              args=('arg1', 'arg2'), kwargs={'arg3': 'arg3'})
+    cleanup_thread.start()
+    cleanup_thread.join()
+    self.assertEqual(cleanup_thread.name, 'test-name')
+    self.assertTrue(event.is_set())
+
+  def testJoinNoTimeout(self):
+    cleanup_thread = _common.CleanupThread(behavior=cleanup)
+    cleanup_thread.start()
+    start_time = time.time()
+    cleanup_thread.join()
+    end_time = time.time()
+    self.assertAlmostEqual(_LONG_TIME, end_time - start_time, delta=_EPSILON)
+
+  def testJoinTimeout(self):
+    cleanup_thread = _common.CleanupThread(behavior=cleanup)
+    cleanup_thread.start()
+    start_time = time.time()
+    cleanup_thread.join(_SHORT_TIME)
+    end_time = time.time()
+    self.assertAlmostEqual(_SHORT_TIME, end_time - start_time, delta=_EPSILON)
+
+  def testJoinTimeoutSlowBehavior(self):
+    cleanup_thread = _common.CleanupThread(behavior=slow_cleanup)
+    cleanup_thread.start()
+    start_time = time.time()
+    cleanup_thread.join(_SHORT_TIME)
+    end_time = time.time()
+    self.assertAlmostEqual(_LONG_TIME, end_time - start_time, delta=_EPSILON)
+
+  def testJoinTimeoutSlowTarget(self):
+    event = threading.Event()
+    def target():
+      event.wait(_LONG_TIME)
+    cleanup_thread = _common.CleanupThread(behavior=cleanup, target=target)
+    cleanup_thread.start()
+    start_time = time.time()
+    cleanup_thread.join(_SHORT_TIME)
+    end_time = time.time()
+    self.assertAlmostEqual(_SHORT_TIME, end_time - start_time, delta=_EPSILON)
+    event.set()
+
+  def testJoinZeroTimeout(self):
+    cleanup_thread = _common.CleanupThread(behavior=cleanup)
+    cleanup_thread.start()
+    start_time = time.time()
+    cleanup_thread.join(0)
+    end_time = time.time()
+    self.assertAlmostEqual(0, end_time - start_time, delta=_EPSILON)
+
+if __name__ == '__main__':
+  unittest.main(verbosity=2)
diff --git a/src/python/grpcio_tests/tests/unit/beta/__init__.py b/src/python/grpcio_tests/tests/unit/beta/__init__.py
new file mode 100644
index 0000000000..7086519106
--- /dev/null
+++ b/src/python/grpcio_tests/tests/unit/beta/__init__.py
@@ -0,0 +1,30 @@
+# 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/beta/_beta_features_test.py b/src/python/grpcio_tests/tests/unit/beta/_beta_features_test.py
new file mode 100644
index 0000000000..3a9701b8eb
--- /dev/null
+++ b/src/python/grpcio_tests/tests/unit/beta/_beta_features_test.py
@@ -0,0 +1,346 @@
+# 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.
+
+"""Tests Face interface compliance of the gRPC Python Beta API."""
+
+import threading
+import unittest
+
+from grpc.beta import implementations
+from grpc.beta import interfaces
+from grpc.framework.common import cardinality
+from grpc.framework.interfaces.face import utilities
+from tests.unit import resources
+from tests.unit.beta import test_utilities
+from tests.unit.framework.common import test_constants
+
+_SERVER_HOST_OVERRIDE = 'foo.test.google.fr'
+
+_PER_RPC_CREDENTIALS_METADATA_KEY = b'my-call-credentials-metadata-key'
+_PER_RPC_CREDENTIALS_METADATA_VALUE = b'my-call-credentials-metadata-value'
+
+_GROUP = 'group'
+_UNARY_UNARY = 'unary-unary'
+_UNARY_STREAM = 'unary-stream'
+_STREAM_UNARY = 'stream-unary'
+_STREAM_STREAM = 'stream-stream'
+
+_REQUEST = b'abc'
+_RESPONSE = b'123'
+
+
+class _Servicer(object):
+
+  def __init__(self):
+    self._condition = threading.Condition()
+    self._peer = None
+    self._serviced = False
+
+  def unary_unary(self, request, context):
+    with self._condition:
+      self._request = request
+      self._peer = context.protocol_context().peer()
+      self._invocation_metadata = context.invocation_metadata()
+      context.protocol_context().disable_next_response_compression()
+      self._serviced = True
+      self._condition.notify_all()
+      return _RESPONSE
+
+  def unary_stream(self, request, context):
+    with self._condition:
+      self._request = request
+      self._peer = context.protocol_context().peer()
+      self._invocation_metadata = context.invocation_metadata()
+      context.protocol_context().disable_next_response_compression()
+      self._serviced = True
+      self._condition.notify_all()
+      return
+      yield
+
+  def stream_unary(self, request_iterator, context):
+    for request in request_iterator:
+      self._request = request
+    with self._condition:
+      self._peer = context.protocol_context().peer()
+      self._invocation_metadata = context.invocation_metadata()
+      context.protocol_context().disable_next_response_compression()
+      self._serviced = True
+      self._condition.notify_all()
+      return _RESPONSE
+
+  def stream_stream(self, request_iterator, context):
+    for request in request_iterator:
+      with self._condition:
+        self._peer = context.protocol_context().peer()
+        context.protocol_context().disable_next_response_compression()
+        yield _RESPONSE
+    with self._condition:
+      self._invocation_metadata = context.invocation_metadata()
+      self._serviced = True
+      self._condition.notify_all()
+
+  def peer(self):
+    with self._condition:
+      return self._peer
+
+  def block_until_serviced(self):
+    with self._condition:
+      while not self._serviced:
+        self._condition.wait()
+
+
+class _BlockingIterator(object):
+
+  def __init__(self, upstream):
+    self._condition = threading.Condition()
+    self._upstream = upstream
+    self._allowed = []
+
+  def __iter__(self):
+    return self
+
+  def __next__(self):
+    return self.next()
+
+  def next(self):
+    with self._condition:
+      while True:
+        if self._allowed is None:
+          raise StopIteration()
+        elif self._allowed:
+          return self._allowed.pop(0)
+        else:
+          self._condition.wait()
+
+  def allow(self):
+    with self._condition:
+      try:
+        self._allowed.append(next(self._upstream))
+      except StopIteration:
+        self._allowed = None
+      self._condition.notify_all()
+
+
+def _metadata_plugin(context, callback):
+  callback([(_PER_RPC_CREDENTIALS_METADATA_KEY,
+             _PER_RPC_CREDENTIALS_METADATA_VALUE)], None)
+
+
+class BetaFeaturesTest(unittest.TestCase):
+
+  def setUp(self):
+    self._servicer = _Servicer()
+    method_implementations = {
+        (_GROUP, _UNARY_UNARY):
+            utilities.unary_unary_inline(self._servicer.unary_unary),
+        (_GROUP, _UNARY_STREAM):
+            utilities.unary_stream_inline(self._servicer.unary_stream),
+        (_GROUP, _STREAM_UNARY):
+            utilities.stream_unary_inline(self._servicer.stream_unary),
+        (_GROUP, _STREAM_STREAM):
+            utilities.stream_stream_inline(self._servicer.stream_stream),
+    }
+
+    cardinalities = {
+        _UNARY_UNARY: cardinality.Cardinality.UNARY_UNARY,
+        _UNARY_STREAM: cardinality.Cardinality.UNARY_STREAM,
+        _STREAM_UNARY: cardinality.Cardinality.STREAM_UNARY,
+        _STREAM_STREAM: cardinality.Cardinality.STREAM_STREAM,
+    }
+
+    server_options = implementations.server_options(
+        thread_pool_size=test_constants.POOL_SIZE)
+    self._server = implementations.server(
+        method_implementations, options=server_options)
+    server_credentials = implementations.ssl_server_credentials(
+        [(resources.private_key(), resources.certificate_chain(),),])
+    port = self._server.add_secure_port('[::]:0', server_credentials)
+    self._server.start()
+    self._channel_credentials = implementations.ssl_channel_credentials(
+        resources.test_root_certificates())
+    self._call_credentials = implementations.metadata_call_credentials(
+        _metadata_plugin)
+    channel = test_utilities.not_really_secure_channel(
+        'localhost', port, self._channel_credentials, _SERVER_HOST_OVERRIDE)
+    stub_options = implementations.stub_options(
+        thread_pool_size=test_constants.POOL_SIZE)
+    self._dynamic_stub = implementations.dynamic_stub(
+        channel, _GROUP, cardinalities, options=stub_options)
+
+  def tearDown(self):
+    self._dynamic_stub = None
+    self._server.stop(test_constants.SHORT_TIMEOUT).wait()
+
+  def test_unary_unary(self):
+    call_options = interfaces.grpc_call_options(
+        disable_compression=True, credentials=self._call_credentials)
+    response = getattr(self._dynamic_stub, _UNARY_UNARY)(
+        _REQUEST, test_constants.LONG_TIMEOUT, protocol_options=call_options)
+    self.assertEqual(_RESPONSE, response)
+    self.assertIsNotNone(self._servicer.peer())
+    invocation_metadata = [(metadatum.key, metadatum.value) for metadatum in
+                           self._servicer._invocation_metadata]
+    self.assertIn(
+        (_PER_RPC_CREDENTIALS_METADATA_KEY,
+         _PER_RPC_CREDENTIALS_METADATA_VALUE),
+        invocation_metadata)
+
+  def test_unary_stream(self):
+    call_options = interfaces.grpc_call_options(
+        disable_compression=True, credentials=self._call_credentials)
+    response_iterator = getattr(self._dynamic_stub, _UNARY_STREAM)(
+        _REQUEST, test_constants.LONG_TIMEOUT, protocol_options=call_options)
+    self._servicer.block_until_serviced()
+    self.assertIsNotNone(self._servicer.peer())
+    invocation_metadata = [(metadatum.key, metadatum.value) for metadatum in
+                           self._servicer._invocation_metadata]
+    self.assertIn(
+        (_PER_RPC_CREDENTIALS_METADATA_KEY,
+         _PER_RPC_CREDENTIALS_METADATA_VALUE),
+        invocation_metadata)
+
+  def test_stream_unary(self):
+    call_options = interfaces.grpc_call_options(
+        credentials=self._call_credentials)
+    request_iterator = _BlockingIterator(iter((_REQUEST,)))
+    response_future = getattr(self._dynamic_stub, _STREAM_UNARY).future(
+        request_iterator, test_constants.LONG_TIMEOUT,
+        protocol_options=call_options)
+    response_future.protocol_context().disable_next_request_compression()
+    request_iterator.allow()
+    response_future.protocol_context().disable_next_request_compression()
+    request_iterator.allow()
+    self._servicer.block_until_serviced()
+    self.assertIsNotNone(self._servicer.peer())
+    self.assertEqual(_RESPONSE, response_future.result())
+    invocation_metadata = [(metadatum.key, metadatum.value) for metadatum in
+                           self._servicer._invocation_metadata]
+    self.assertIn(
+        (_PER_RPC_CREDENTIALS_METADATA_KEY,
+         _PER_RPC_CREDENTIALS_METADATA_VALUE),
+        invocation_metadata)
+
+  def test_stream_stream(self):
+    call_options = interfaces.grpc_call_options(
+        credentials=self._call_credentials)
+    request_iterator = _BlockingIterator(iter((_REQUEST,)))
+    response_iterator = getattr(self._dynamic_stub, _STREAM_STREAM)(
+        request_iterator, test_constants.SHORT_TIMEOUT,
+        protocol_options=call_options)
+    response_iterator.protocol_context().disable_next_request_compression()
+    request_iterator.allow()
+    response = next(response_iterator)
+    response_iterator.protocol_context().disable_next_request_compression()
+    request_iterator.allow()
+    self._servicer.block_until_serviced()
+    self.assertIsNotNone(self._servicer.peer())
+    self.assertEqual(_RESPONSE, response)
+    invocation_metadata = [(metadatum.key, metadatum.value) for metadatum in
+                           self._servicer._invocation_metadata]
+    self.assertIn(
+        (_PER_RPC_CREDENTIALS_METADATA_KEY,
+         _PER_RPC_CREDENTIALS_METADATA_VALUE),
+        invocation_metadata)
+
+
+class ContextManagementAndLifecycleTest(unittest.TestCase):
+
+  def setUp(self):
+    self._servicer = _Servicer()
+    self._method_implementations = {
+        (_GROUP, _UNARY_UNARY):
+            utilities.unary_unary_inline(self._servicer.unary_unary),
+        (_GROUP, _UNARY_STREAM):
+            utilities.unary_stream_inline(self._servicer.unary_stream),
+        (_GROUP, _STREAM_UNARY):
+            utilities.stream_unary_inline(self._servicer.stream_unary),
+        (_GROUP, _STREAM_STREAM):
+            utilities.stream_stream_inline(self._servicer.stream_stream),
+    }
+
+    self._cardinalities = {
+        _UNARY_UNARY: cardinality.Cardinality.UNARY_UNARY,
+        _UNARY_STREAM: cardinality.Cardinality.UNARY_STREAM,
+        _STREAM_UNARY: cardinality.Cardinality.STREAM_UNARY,
+        _STREAM_STREAM: cardinality.Cardinality.STREAM_STREAM,
+    }
+
+    self._server_options = implementations.server_options(
+        thread_pool_size=test_constants.POOL_SIZE)
+    self._server_credentials = implementations.ssl_server_credentials(
+        [(resources.private_key(), resources.certificate_chain(),),])
+    self._channel_credentials = implementations.ssl_channel_credentials(
+        resources.test_root_certificates())
+    self._stub_options = implementations.stub_options(
+        thread_pool_size=test_constants.POOL_SIZE)
+
+  def test_stub_context(self):
+    server = implementations.server(
+        self._method_implementations, options=self._server_options)
+    port = server.add_secure_port('[::]:0', self._server_credentials)
+    server.start()
+
+    channel = test_utilities.not_really_secure_channel(
+        'localhost', port, self._channel_credentials, _SERVER_HOST_OVERRIDE)
+    dynamic_stub = implementations.dynamic_stub(
+        channel, _GROUP, self._cardinalities, options=self._stub_options)
+    for _ in range(100):
+      with dynamic_stub:
+        pass
+    for _ in range(10):
+      with dynamic_stub:
+        call_options = interfaces.grpc_call_options(
+            disable_compression=True)
+        response = getattr(dynamic_stub, _UNARY_UNARY)(
+            _REQUEST, test_constants.LONG_TIMEOUT,
+            protocol_options=call_options)
+        self.assertEqual(_RESPONSE, response)
+        self.assertIsNotNone(self._servicer.peer())
+
+    server.stop(test_constants.SHORT_TIMEOUT).wait()
+
+  def test_server_lifecycle(self):
+    for _ in range(100):
+      server = implementations.server(
+          self._method_implementations, options=self._server_options)
+      port = server.add_secure_port('[::]:0', self._server_credentials)
+      server.start()
+      server.stop(test_constants.SHORT_TIMEOUT).wait()
+    for _ in range(100):
+      server = implementations.server(
+          self._method_implementations, options=self._server_options)
+      server.add_secure_port('[::]:0', self._server_credentials)
+      server.add_insecure_port('[::]:0')
+      with server:
+        server.stop(test_constants.SHORT_TIMEOUT)
+      server.stop(test_constants.SHORT_TIMEOUT)
+
+
+if __name__ == '__main__':
+  unittest.main(verbosity=2)
diff --git a/src/python/grpcio_tests/tests/unit/beta/_connectivity_channel_test.py b/src/python/grpcio_tests/tests/unit/beta/_connectivity_channel_test.py
new file mode 100644
index 0000000000..5d826a269d
--- /dev/null
+++ b/src/python/grpcio_tests/tests/unit/beta/_connectivity_channel_test.py
@@ -0,0 +1,48 @@
+# 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.
+
+"""Tests of grpc.beta._connectivity_channel."""
+
+import unittest
+
+from grpc.beta import interfaces
+
+
+class ConnectivityStatesTest(unittest.TestCase):
+
+  def testBetaConnectivityStates(self):
+    self.assertIsNotNone(interfaces.ChannelConnectivity.IDLE)
+    self.assertIsNotNone(interfaces.ChannelConnectivity.CONNECTING)
+    self.assertIsNotNone(interfaces.ChannelConnectivity.READY)
+    self.assertIsNotNone(interfaces.ChannelConnectivity.TRANSIENT_FAILURE)
+    self.assertIsNotNone(interfaces.ChannelConnectivity.FATAL_FAILURE)
+
+
+if __name__ == '__main__':
+  unittest.main(verbosity=2)
diff --git a/src/python/grpcio_tests/tests/unit/beta/_face_interface_test.py b/src/python/grpcio_tests/tests/unit/beta/_face_interface_test.py
new file mode 100644
index 0000000000..3a67516906
--- /dev/null
+++ b/src/python/grpcio_tests/tests/unit/beta/_face_interface_test.py
@@ -0,0 +1,140 @@
+# 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.
+
+"""Tests Face interface compliance of the gRPC Python Beta API."""
+
+import collections
+import unittest
+
+import six
+
+from grpc.beta import implementations
+from grpc.beta import interfaces
+from tests.unit import resources
+from tests.unit import test_common as grpc_test_common
+from tests.unit.beta import test_utilities
+from tests.unit.framework.common import test_constants
+from tests.unit.framework.interfaces.face import test_cases
+from tests.unit.framework.interfaces.face import test_interfaces
+
+_SERVER_HOST_OVERRIDE = 'foo.test.google.fr'
+
+
+class _SerializationBehaviors(
+    collections.namedtuple(
+        '_SerializationBehaviors',
+        ('request_serializers', 'request_deserializers', 'response_serializers',
+         'response_deserializers',))):
+  pass
+
+
+def _serialization_behaviors_from_test_methods(test_methods):
+  request_serializers = {}
+  request_deserializers = {}
+  response_serializers = {}
+  response_deserializers = {}
+  for (group, method), test_method in six.iteritems(test_methods):
+    request_serializers[group, method] = test_method.serialize_request
+    request_deserializers[group, method] = test_method.deserialize_request
+    response_serializers[group, method] = test_method.serialize_response
+    response_deserializers[group, method] = test_method.deserialize_response
+  return _SerializationBehaviors(
+      request_serializers, request_deserializers, response_serializers,
+      response_deserializers)
+
+
+class _Implementation(test_interfaces.Implementation):
+
+  def instantiate(
+      self, methods, method_implementations, multi_method_implementation):
+    serialization_behaviors = _serialization_behaviors_from_test_methods(
+        methods)
+    # TODO(nathaniel): Add a "groups" attribute to _digest.TestServiceDigest.
+    service = next(iter(methods))[0]
+    # TODO(nathaniel): Add a "cardinalities_by_group" attribute to
+    # _digest.TestServiceDigest.
+    cardinalities = {
+        method: method_object.cardinality()
+        for (group, method), method_object in six.iteritems(methods)}
+
+    server_options = implementations.server_options(
+        request_deserializers=serialization_behaviors.request_deserializers,
+        response_serializers=serialization_behaviors.response_serializers,
+        thread_pool_size=test_constants.POOL_SIZE)
+    server = implementations.server(
+        method_implementations, options=server_options)
+    server_credentials = implementations.ssl_server_credentials(
+        [(resources.private_key(), resources.certificate_chain(),),])
+    port = server.add_secure_port('[::]:0', server_credentials)
+    server.start()
+    channel_credentials = implementations.ssl_channel_credentials(
+        resources.test_root_certificates())
+    channel = test_utilities.not_really_secure_channel(
+        'localhost', port, channel_credentials, _SERVER_HOST_OVERRIDE)
+    stub_options = implementations.stub_options(
+        request_serializers=serialization_behaviors.request_serializers,
+        response_deserializers=serialization_behaviors.response_deserializers,
+        thread_pool_size=test_constants.POOL_SIZE)
+    generic_stub = implementations.generic_stub(channel, options=stub_options)
+    dynamic_stub = implementations.dynamic_stub(
+        channel, service, cardinalities, options=stub_options)
+    return generic_stub, {service: dynamic_stub}, server
+
+  def destantiate(self, memo):
+    memo.stop(test_constants.SHORT_TIMEOUT).wait()
+
+  def invocation_metadata(self):
+    return grpc_test_common.INVOCATION_INITIAL_METADATA
+
+  def initial_metadata(self):
+    return grpc_test_common.SERVICE_INITIAL_METADATA
+
+  def terminal_metadata(self):
+    return grpc_test_common.SERVICE_TERMINAL_METADATA
+
+  def code(self):
+    return interfaces.StatusCode.OK
+
+  def details(self):
+    return grpc_test_common.DETAILS
+
+  def metadata_transmitted(self, original_metadata, transmitted_metadata):
+    return original_metadata is None or grpc_test_common.metadata_transmitted(
+        original_metadata, transmitted_metadata)
+
+
+def load_tests(loader, tests, pattern):
+  return unittest.TestSuite(
+      tests=tuple(
+          loader.loadTestsFromTestCase(test_case_class)
+          for test_case_class in test_cases.test_cases(_Implementation())))
+
+
+if __name__ == '__main__':
+  unittest.main(verbosity=2)
diff --git a/src/python/grpcio_tests/tests/unit/beta/_implementations_test.py b/src/python/grpcio_tests/tests/unit/beta/_implementations_test.py
new file mode 100644
index 0000000000..127f93e9bb
--- /dev/null
+++ b/src/python/grpcio_tests/tests/unit/beta/_implementations_test.py
@@ -0,0 +1,70 @@
+# 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.
+
+"""Tests the implementations module of the gRPC Python Beta API."""
+
+import datetime
+import unittest
+
+from oauth2client import client as oauth2client_client
+
+from grpc.beta import implementations
+from tests.unit import resources
+
+
+class ChannelCredentialsTest(unittest.TestCase):
+
+  def test_runtime_provided_root_certificates(self):
+    channel_credentials = implementations.ssl_channel_credentials()
+    self.assertIsInstance(
+        channel_credentials, implementations.ChannelCredentials)
+  
+  def test_application_provided_root_certificates(self):
+    channel_credentials = implementations.ssl_channel_credentials(
+        resources.test_root_certificates())
+    self.assertIsInstance(
+        channel_credentials, implementations.ChannelCredentials)
+
+
+class CallCredentialsTest(unittest.TestCase):
+
+  def test_google_call_credentials(self):
+    creds = oauth2client_client.GoogleCredentials(
+        'token', 'client_id', 'secret', 'refresh_token',
+        datetime.datetime(2008, 6, 24), 'https://refresh.uri.com/',
+        'user_agent')
+    call_creds = implementations.google_call_credentials(creds)
+    self.assertIsInstance(call_creds, implementations.CallCredentials)
+
+  def test_access_token_call_credentials(self):
+    call_creds = implementations.access_token_call_credentials('token')
+    self.assertIsInstance(call_creds, implementations.CallCredentials)
+
+if __name__ == '__main__':
+  unittest.main(verbosity=2)
diff --git a/src/python/grpcio_tests/tests/unit/beta/_not_found_test.py b/src/python/grpcio_tests/tests/unit/beta/_not_found_test.py
new file mode 100644
index 0000000000..37b8c49120
--- /dev/null
+++ b/src/python/grpcio_tests/tests/unit/beta/_not_found_test.py
@@ -0,0 +1,75 @@
+# 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.
+
+"""Tests of RPC-method-not-found behavior."""
+
+import unittest
+
+from grpc.beta import implementations
+from grpc.beta import interfaces
+from grpc.framework.interfaces.face import face
+from tests.unit.framework.common import test_constants
+
+
+class NotFoundTest(unittest.TestCase):
+
+  def setUp(self):
+    self._server = implementations.server({})
+    port = self._server.add_insecure_port('[::]:0')
+    channel = implementations.insecure_channel('localhost', port)
+    self._generic_stub = implementations.generic_stub(channel)
+    self._server.start()
+
+  def tearDown(self):
+    self._server.stop(0).wait()
+    self._generic_stub = None
+
+  def test_blocking_unary_unary_not_found(self):
+    with self.assertRaises(face.LocalError) as exception_assertion_context:
+      self._generic_stub.blocking_unary_unary(
+          'groop', 'meffod', b'abc', test_constants.LONG_TIMEOUT,
+          with_call=True)
+    self.assertIs(
+        exception_assertion_context.exception.code,
+        interfaces.StatusCode.UNIMPLEMENTED)
+
+  def test_future_stream_unary_not_found(self):
+    rpc_future = self._generic_stub.future_stream_unary(
+        'grupe', 'mevvod', [b'def'], test_constants.LONG_TIMEOUT)
+    with self.assertRaises(face.LocalError) as exception_assertion_context:
+      rpc_future.result()
+    self.assertIs(
+        exception_assertion_context.exception.code,
+        interfaces.StatusCode.UNIMPLEMENTED)
+    self.assertIs(
+        rpc_future.exception().code, interfaces.StatusCode.UNIMPLEMENTED)
+
+
+if __name__ == '__main__':
+  unittest.main(verbosity=2)
diff --git a/src/python/grpcio_tests/tests/unit/beta/_utilities_test.py b/src/python/grpcio_tests/tests/unit/beta/_utilities_test.py
new file mode 100644
index 0000000000..90fe10c77c
--- /dev/null
+++ b/src/python/grpcio_tests/tests/unit/beta/_utilities_test.py
@@ -0,0 +1,108 @@
+# 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.
+
+"""Tests of grpc.beta.utilities."""
+
+import threading
+import time
+import unittest
+
+from grpc.beta import implementations
+from grpc.beta import utilities
+from grpc.framework.foundation import future
+from tests.unit.framework.common import test_constants
+
+
+class _Callback(object):
+
+  def __init__(self):
+    self._condition = threading.Condition()
+    self._value = None
+
+  def accept_value(self, value):
+    with self._condition:
+      self._value = value
+      self._condition.notify_all()
+
+  def block_until_called(self):
+    with self._condition:
+      while self._value is None:
+        self._condition.wait()
+      return self._value
+
+
+class ChannelConnectivityTest(unittest.TestCase):
+
+  def test_lonely_channel_connectivity(self):
+    channel = implementations.insecure_channel('localhost', 12345)
+    callback = _Callback()
+
+    ready_future = utilities.channel_ready_future(channel)
+    ready_future.add_done_callback(callback.accept_value)
+    with self.assertRaises(future.TimeoutError):
+      ready_future.result(test_constants.SHORT_TIMEOUT)
+    self.assertFalse(ready_future.cancelled())
+    self.assertFalse(ready_future.done())
+    self.assertTrue(ready_future.running())
+    ready_future.cancel()
+    value_passed_to_callback = callback.block_until_called()
+    self.assertIs(ready_future, value_passed_to_callback)
+    self.assertTrue(ready_future.cancelled())
+    self.assertTrue(ready_future.done())
+    self.assertFalse(ready_future.running())
+
+  def test_immediately_connectable_channel_connectivity(self):
+    server = implementations.server({})
+    port = server.add_insecure_port('[::]:0')
+    server.start()
+    channel = implementations.insecure_channel('localhost', port)
+    callback = _Callback()
+
+    try:
+      ready_future = utilities.channel_ready_future(channel)
+      ready_future.add_done_callback(callback.accept_value)
+      self.assertIsNone(
+          ready_future.result(test_constants.SHORT_TIMEOUT))
+      value_passed_to_callback = callback.block_until_called()
+      self.assertIs(ready_future, value_passed_to_callback)
+      self.assertFalse(ready_future.cancelled())
+      self.assertTrue(ready_future.done())
+      self.assertFalse(ready_future.running())
+      # Cancellation after maturity has no effect.
+      ready_future.cancel()
+      self.assertFalse(ready_future.cancelled())
+      self.assertTrue(ready_future.done())
+      self.assertFalse(ready_future.running())
+    finally:
+      ready_future.cancel()
+      server.stop(0)
+
+
+if __name__ == '__main__':
+  unittest.main(verbosity=2)
diff --git a/src/python/grpcio_tests/tests/unit/beta/test_utilities.py b/src/python/grpcio_tests/tests/unit/beta/test_utilities.py
new file mode 100644
index 0000000000..692da9c97d
--- /dev/null
+++ b/src/python/grpcio_tests/tests/unit/beta/test_utilities.py
@@ -0,0 +1,55 @@
+# 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.
+
+"""Test-appropriate entry points into the gRPC Python Beta API."""
+
+import grpc
+from grpc.beta import implementations
+
+
+def not_really_secure_channel(
+    host, port, channel_credentials, server_host_override):
+  """Creates an insecure Channel to a remote host.
+
+  Args:
+    host: The name of the remote host to which to connect.
+    port: The port of the remote host to which to connect.
+    channel_credentials: The implementations.ChannelCredentials with which to
+      connect.
+    server_host_override: The target name used for SSL host name checking.
+
+  Returns:
+    An implementations.Channel to the remote host through which RPCs may be
+      conducted.
+  """
+  target = '%s:%d' % (host, port)
+  channel = grpc.secure_channel(
+      target, channel_credentials,
+      (('grpc.ssl_target_name_override', server_host_override,),))
+  return implementations.Channel(channel)
diff --git a/src/python/grpcio_tests/tests/unit/credentials/README b/src/python/grpcio_tests/tests/unit/credentials/README
new file mode 100644
index 0000000000..cb20dcb49f
--- /dev/null
+++ b/src/python/grpcio_tests/tests/unit/credentials/README
@@ -0,0 +1 @@
+These are test keys *NOT* to be used in production.
diff --git a/src/python/grpcio_tests/tests/unit/credentials/ca.pem b/src/python/grpcio_tests/tests/unit/credentials/ca.pem
new file mode 100755
index 0000000000..6c8511a73c
--- /dev/null
+++ b/src/python/grpcio_tests/tests/unit/credentials/ca.pem
@@ -0,0 +1,15 @@
+-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----
diff --git a/src/python/grpcio_tests/tests/unit/credentials/server1.key b/src/python/grpcio_tests/tests/unit/credentials/server1.key
new file mode 100755
index 0000000000..143a5b8765
--- /dev/null
+++ b/src/python/grpcio_tests/tests/unit/credentials/server1.key
@@ -0,0 +1,16 @@
+-----BEGIN PRIVATE KEY-----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+-----END PRIVATE KEY-----
diff --git a/src/python/grpcio_tests/tests/unit/credentials/server1.pem b/src/python/grpcio_tests/tests/unit/credentials/server1.pem
new file mode 100755
index 0000000000..f3d43fcc5b
--- /dev/null
+++ b/src/python/grpcio_tests/tests/unit/credentials/server1.pem
@@ -0,0 +1,16 @@
+-----BEGIN CERTIFICATE-----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-----END CERTIFICATE-----
diff --git a/src/python/grpcio_tests/tests/unit/framework/__init__.py b/src/python/grpcio_tests/tests/unit/framework/__init__.py
new file mode 100644
index 0000000000..7086519106
--- /dev/null
+++ b/src/python/grpcio_tests/tests/unit/framework/__init__.py
@@ -0,0 +1,30 @@
+# 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/framework/common/__init__.py b/src/python/grpcio_tests/tests/unit/framework/common/__init__.py
new file mode 100644
index 0000000000..7086519106
--- /dev/null
+++ b/src/python/grpcio_tests/tests/unit/framework/common/__init__.py
@@ -0,0 +1,30 @@
+# 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/framework/common/test_constants.py b/src/python/grpcio_tests/tests/unit/framework/common/test_constants.py
new file mode 100644
index 0000000000..b6682d396c
--- /dev/null
+++ b/src/python/grpcio_tests/tests/unit/framework/common/test_constants.py
@@ -0,0 +1,61 @@
+# 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.
+
+"""Constants shared among tests throughout RPC Framework."""
+
+# Value for maximum duration in seconds that a test is allowed for its actual
+# behavioral logic, excluding all time spent deliberately waiting in the test.
+TIME_ALLOWANCE = 10
+# Value for maximum duration in seconds of RPCs that may time out as part of a
+# test.
+SHORT_TIMEOUT = 4
+# Absurdly large value for maximum duration in seconds for should-not-time-out
+# RPCs made during tests.
+LONG_TIMEOUT = 3000
+# Values to supply on construction of an object that will service RPCs; these
+# should not be used as the actual timeout values of any RPCs made during tests.
+DEFAULT_TIMEOUT = 300
+MAXIMUM_TIMEOUT = 3600
+
+# The number of payloads to transmit in streaming tests.
+STREAM_LENGTH = 200
+
+# The size of payloads to transmit in tests.
+PAYLOAD_SIZE = 256 * 1024 + 17
+
+# The concurrency to use in tests of concurrent RPCs that will not create as
+# many threads as RPCs.
+RPC_CONCURRENCY = 200
+
+# The concurrency to use in tests of concurrent RPCs that will create as many
+# threads as RPCs.
+THREAD_CONCURRENCY = 25
+
+# The size of thread pools to use in tests.
+POOL_SIZE = 10
diff --git a/src/python/grpcio_tests/tests/unit/framework/common/test_control.py b/src/python/grpcio_tests/tests/unit/framework/common/test_control.py
new file mode 100644
index 0000000000..088e2f8b88
--- /dev/null
+++ b/src/python/grpcio_tests/tests/unit/framework/common/test_control.py
@@ -0,0 +1,113 @@
+# 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.
+
+"""Code for instructing systems under test to block or fail."""
+
+import abc
+import contextlib
+import threading
+
+import six
+
+
+class Defect(Exception):
+  """Simulates a programming defect raised into in a system under test.
+
+  Use of a standard exception type is too easily misconstrued as an actual
+  defect in either the test infrastructure or the system under test.
+  """
+
+
+class Control(six.with_metaclass(abc.ABCMeta)):
+  """An object that accepts program control from a system under test.
+
+  Systems under test passed a Control should call its control() method
+  frequently during execution. The control() method may block, raise an
+  exception, or do nothing, all according to the enclosing test's desire for
+  the system under test to simulate hanging, failing, or functioning.
+  """
+
+  @abc.abstractmethod
+  def control(self):
+    """Potentially does anything."""
+    raise NotImplementedError()
+
+
+class PauseFailControl(Control):
+  """A Control that can be used to pause or fail code under control.
+
+  This object is only safe for use from two threads: one of the system under
+  test calling control and the other from the test system calling pause,
+  block_until_paused, and fail.
+  """
+
+  def __init__(self):
+    self._condition = threading.Condition()
+    self._pause = False
+    self._paused = False
+    self._fail = False
+
+  def control(self):
+    with self._condition:
+      if self._fail:
+        raise Defect()
+
+      while self._pause:
+        self._paused = True
+        self._condition.notify_all()
+        self._condition.wait()
+      self._paused = False
+
+  @contextlib.contextmanager
+  def pause(self):
+    """Pauses code under control while controlling code is in context."""
+    with self._condition:
+      self._pause = True
+    yield
+    with self._condition:
+      self._pause = False
+      self._condition.notify_all()
+
+  def block_until_paused(self):
+    """Blocks controlling code until code under control is paused.
+
+    May only be called within the context of a pause call.
+    """
+    with self._condition:
+      while not self._paused:
+        self._condition.wait()
+
+  @contextlib.contextmanager
+  def fail(self):
+    """Fails code under control while controlling code is in context."""
+    with self._condition:
+      self._fail = True
+    yield
+    with self._condition:
+      self._fail = False
diff --git a/src/python/grpcio_tests/tests/unit/framework/common/test_coverage.py b/src/python/grpcio_tests/tests/unit/framework/common/test_coverage.py
new file mode 100644
index 0000000000..ea2d2812ce
--- /dev/null
+++ b/src/python/grpcio_tests/tests/unit/framework/common/test_coverage.py
@@ -0,0 +1,117 @@
+# 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.
+
+"""Governs coverage for tests of RPCs throughout RPC Framework."""
+
+import abc
+
+import six
+
+# This code is designed for use with the unittest module.
+# pylint: disable=invalid-name
+
+
+class Coverage(six.with_metaclass(abc.ABCMeta)):
+  """Specification of test coverage."""
+
+  @abc.abstractmethod
+  def testSuccessfulUnaryRequestUnaryResponse(self):
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def testSuccessfulUnaryRequestStreamResponse(self):
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def testSuccessfulStreamRequestUnaryResponse(self):
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def testSuccessfulStreamRequestStreamResponse(self):
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def testSequentialInvocations(self):
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def testParallelInvocations(self):
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def testWaitingForSomeButNotAllParallelInvocations(self):
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def testCancelledUnaryRequestUnaryResponse(self):
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def testCancelledUnaryRequestStreamResponse(self):
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def testCancelledStreamRequestUnaryResponse(self):
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def testCancelledStreamRequestStreamResponse(self):
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def testExpiredUnaryRequestUnaryResponse(self):
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def testExpiredUnaryRequestStreamResponse(self):
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def testExpiredStreamRequestUnaryResponse(self):
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def testExpiredStreamRequestStreamResponse(self):
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def testFailedUnaryRequestUnaryResponse(self):
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def testFailedUnaryRequestStreamResponse(self):
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def testFailedStreamRequestUnaryResponse(self):
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def testFailedStreamRequestStreamResponse(self):
+    raise NotImplementedError()
diff --git a/src/python/grpcio_tests/tests/unit/framework/core/__init__.py b/src/python/grpcio_tests/tests/unit/framework/core/__init__.py
new file mode 100644
index 0000000000..7086519106
--- /dev/null
+++ b/src/python/grpcio_tests/tests/unit/framework/core/__init__.py
@@ -0,0 +1,30 @@
+# 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/framework/foundation/__init__.py b/src/python/grpcio_tests/tests/unit/framework/foundation/__init__.py
new file mode 100644
index 0000000000..7086519106
--- /dev/null
+++ b/src/python/grpcio_tests/tests/unit/framework/foundation/__init__.py
@@ -0,0 +1,30 @@
+# 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/framework/foundation/_logging_pool_test.py b/src/python/grpcio_tests/tests/unit/framework/foundation/_logging_pool_test.py
new file mode 100644
index 0000000000..330e445d43
--- /dev/null
+++ b/src/python/grpcio_tests/tests/unit/framework/foundation/_logging_pool_test.py
@@ -0,0 +1,88 @@
+# 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.
+
+"""Tests for grpc.framework.foundation.logging_pool."""
+
+import threading
+import unittest
+
+from grpc.framework.foundation import logging_pool
+
+_POOL_SIZE = 16
+
+
+class _CallableObject(object):
+
+  def __init__(self):
+    self._lock = threading.Lock()
+    self._passed_values = []
+
+  def __call__(self, value):
+    with self._lock:
+      self._passed_values.append(value)
+
+  def passed_values(self):
+    with self._lock:
+      return tuple(self._passed_values)
+
+
+class LoggingPoolTest(unittest.TestCase):
+
+  def testUpAndDown(self):
+    pool = logging_pool.pool(_POOL_SIZE)
+    pool.shutdown(wait=True)
+
+    with logging_pool.pool(_POOL_SIZE) as pool:
+      self.assertIsNotNone(pool)
+
+  def testTaskExecuted(self):
+    test_list = []
+
+    with logging_pool.pool(_POOL_SIZE) as pool:
+      pool.submit(lambda: test_list.append(object())).result()
+
+    self.assertTrue(test_list)
+
+  def testException(self):
+    with logging_pool.pool(_POOL_SIZE) as pool:
+      raised_exception = pool.submit(lambda: 1/0).exception()
+
+    self.assertIsNotNone(raised_exception)
+
+  def testCallableObjectExecuted(self):
+    callable_object = _CallableObject()
+    passed_object = object()
+    with logging_pool.pool(_POOL_SIZE) as pool:
+      future = pool.submit(callable_object, passed_object)
+    self.assertIsNone(future.result())
+    self.assertSequenceEqual((passed_object,), callable_object.passed_values())
+
+
+if __name__ == '__main__':
+  unittest.main(verbosity=2)
diff --git a/src/python/grpcio_tests/tests/unit/framework/foundation/stream_testing.py b/src/python/grpcio_tests/tests/unit/framework/foundation/stream_testing.py
new file mode 100644
index 0000000000..098a53d5e7
--- /dev/null
+++ b/src/python/grpcio_tests/tests/unit/framework/foundation/stream_testing.py
@@ -0,0 +1,73 @@
+# 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.
+
+"""Utilities for testing stream-related code."""
+
+from grpc.framework.foundation import stream
+
+
+class TestConsumer(stream.Consumer):
+  """A stream.Consumer instrumented for testing.
+
+  Attributes:
+    calls: A sequence of value-termination pairs describing the history of calls
+      made on this object.
+  """
+
+  def __init__(self):
+    self.calls = []
+
+  def consume(self, value):
+    """See stream.Consumer.consume for specification."""
+    self.calls.append((value, False))
+
+  def terminate(self):
+    """See stream.Consumer.terminate for specification."""
+    self.calls.append((None, True))
+
+  def consume_and_terminate(self, value):
+    """See stream.Consumer.consume_and_terminate for specification."""
+    self.calls.append((value, True))
+
+  def is_legal(self):
+    """Reports whether or not a legal sequence of calls has been made."""
+    terminated = False
+    for value, terminal in self.calls:
+      if terminated:
+        return False
+      elif terminal:
+        terminated = True
+      elif value is None:
+        return False
+    else:  # pylint: disable=useless-else-on-loop
+      return True
+
+  def values(self):
+    """Returns the sequence of values that have been passed to this Consumer."""
+    return [value for value, _ in self.calls if value]
diff --git a/src/python/grpcio_tests/tests/unit/framework/interfaces/__init__.py b/src/python/grpcio_tests/tests/unit/framework/interfaces/__init__.py
new file mode 100644
index 0000000000..7086519106
--- /dev/null
+++ b/src/python/grpcio_tests/tests/unit/framework/interfaces/__init__.py
@@ -0,0 +1,30 @@
+# 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/framework/interfaces/base/__init__.py b/src/python/grpcio_tests/tests/unit/framework/interfaces/base/__init__.py
new file mode 100644
index 0000000000..7086519106
--- /dev/null
+++ b/src/python/grpcio_tests/tests/unit/framework/interfaces/base/__init__.py
@@ -0,0 +1,30 @@
+# 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/framework/interfaces/base/_control.py b/src/python/grpcio_tests/tests/unit/framework/interfaces/base/_control.py
new file mode 100644
index 0000000000..0eb38abf22
--- /dev/null
+++ b/src/python/grpcio_tests/tests/unit/framework/interfaces/base/_control.py
@@ -0,0 +1,570 @@
+# 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.
+
+"""Part of the tests of the base interface of RPC Framework."""
+
+from __future__ import division
+
+import abc
+import collections
+import enum
+import random  # pylint: disable=unused-import
+import threading
+import time
+
+import six
+
+from grpc.framework.interfaces.base import base
+from tests.unit.framework.common import test_constants
+from tests.unit.framework.interfaces.base import _sequence
+from tests.unit.framework.interfaces.base import _state
+from tests.unit.framework.interfaces.base import test_interfaces  # pylint: disable=unused-import
+
+_GROUP = 'base test cases test group'
+_METHOD = 'base test cases test method'
+
+_PAYLOAD_RANDOM_SECTION_MAXIMUM_SIZE = test_constants.PAYLOAD_SIZE // 20
+_MINIMUM_PAYLOAD_SIZE = test_constants.PAYLOAD_SIZE // 600
+
+
+def _create_payload(randomness):
+  length = randomness.randint(
+      _MINIMUM_PAYLOAD_SIZE, test_constants.PAYLOAD_SIZE)
+  random_section_length = randomness.randint(
+      0, min(_PAYLOAD_RANDOM_SECTION_MAXIMUM_SIZE, length))
+  random_section = bytes(
+      bytearray(
+          randomness.getrandbits(8) for _ in range(random_section_length)))
+  sevens_section = b'\x07' * (length - random_section_length)
+  return b''.join(randomness.sample((random_section, sevens_section), 2))
+
+
+def _anything_in_flight(state):
+  return (
+      state.invocation_initial_metadata_in_flight is not None or
+      state.invocation_payloads_in_flight or
+      state.invocation_completion_in_flight is not None or
+      state.service_initial_metadata_in_flight is not None or
+      state.service_payloads_in_flight or
+      state.service_completion_in_flight is not None or
+      0 < state.invocation_allowance_in_flight or
+      0 < state.service_allowance_in_flight
+  )
+
+
+def _verify_service_advance_and_update_state(
+    initial_metadata, payload, completion, allowance, state, implementation):
+  if initial_metadata is not None:
+    if state.invocation_initial_metadata_received:
+      return 'Later invocation initial metadata received: %s' % (
+          initial_metadata,)
+    if state.invocation_payloads_received:
+      return 'Invocation initial metadata received after payloads: %s' % (
+          state.invocation_payloads_received)
+    if state.invocation_completion_received:
+      return 'Invocation initial metadata received after invocation completion!'
+    if not implementation.metadata_transmitted(
+        state.invocation_initial_metadata_in_flight, initial_metadata):
+      return 'Invocation initial metadata maltransmitted: %s, %s' % (
+          state.invocation_initial_metadata_in_flight, initial_metadata)
+    else:
+      state.invocation_initial_metadata_in_flight = None
+      state.invocation_initial_metadata_received = True
+
+  if payload is not None:
+    if state.invocation_completion_received:
+      return 'Invocation payload received after invocation completion!'
+    elif not state.invocation_payloads_in_flight:
+      return 'Invocation payload "%s" received but not in flight!' % (payload,)
+    elif state.invocation_payloads_in_flight[0] != payload:
+      return 'Invocation payload mismatch: %s, %s' % (
+          state.invocation_payloads_in_flight[0], payload)
+    elif state.service_side_invocation_allowance < 1:
+      return 'Disallowed invocation payload!'
+    else:
+      state.invocation_payloads_in_flight.pop(0)
+      state.invocation_payloads_received += 1
+      state.service_side_invocation_allowance -= 1
+
+  if completion is not None:
+    if state.invocation_completion_received:
+      return 'Later invocation completion received: %s' % (completion,)
+    elif not implementation.completion_transmitted(
+        state.invocation_completion_in_flight, completion):
+      return 'Invocation completion maltransmitted: %s, %s' % (
+          state.invocation_completion_in_flight, completion)
+    else:
+      state.invocation_completion_in_flight = None
+      state.invocation_completion_received = True
+
+  if allowance is not None:
+    if allowance <= 0:
+      return 'Illegal allowance value: %s' % (allowance,)
+    else:
+      state.service_allowance_in_flight -= allowance
+      state.service_side_service_allowance += allowance
+
+
+def _verify_invocation_advance_and_update_state(
+    initial_metadata, payload, completion, allowance, state, implementation):
+  if initial_metadata is not None:
+    if state.service_initial_metadata_received:
+      return 'Later service initial metadata received: %s' % (initial_metadata,)
+    if state.service_payloads_received:
+      return 'Service initial metadata received after service payloads: %s' % (
+          state.service_payloads_received)
+    if state.service_completion_received:
+      return 'Service initial metadata received after service completion!'
+    if not implementation.metadata_transmitted(
+        state.service_initial_metadata_in_flight, initial_metadata):
+      return 'Service initial metadata maltransmitted: %s, %s' % (
+          state.service_initial_metadata_in_flight, initial_metadata)
+    else:
+      state.service_initial_metadata_in_flight = None
+      state.service_initial_metadata_received = True
+
+  if payload is not None:
+    if state.service_completion_received:
+      return 'Service payload received after service completion!'
+    elif not state.service_payloads_in_flight:
+      return 'Service payload "%s" received but not in flight!' % (payload,)
+    elif state.service_payloads_in_flight[0] != payload:
+      return 'Service payload mismatch: %s, %s' % (
+          state.invocation_payloads_in_flight[0], payload)
+    elif state.invocation_side_service_allowance < 1:
+      return 'Disallowed service payload!'
+    else:
+      state.service_payloads_in_flight.pop(0)
+      state.service_payloads_received += 1
+      state.invocation_side_service_allowance -= 1
+
+  if completion is not None:
+    if state.service_completion_received:
+      return 'Later service completion received: %s' % (completion,)
+    elif not implementation.completion_transmitted(
+        state.service_completion_in_flight, completion):
+      return 'Service completion maltransmitted: %s, %s' % (
+          state.service_completion_in_flight, completion)
+    else:
+      state.service_completion_in_flight = None
+      state.service_completion_received = True
+
+  if allowance is not None:
+    if allowance <= 0:
+      return 'Illegal allowance value: %s' % (allowance,)
+    else:
+      state.invocation_allowance_in_flight -= allowance
+      state.invocation_side_service_allowance += allowance
+
+
+class Invocation(
+    collections.namedtuple(
+        'Invocation',
+        ('group', 'method', 'subscription_kind', 'timeout', 'initial_metadata',
+         'payload', 'completion',))):
+  """A description of operation invocation.
+
+  Attributes:
+    group: The group identifier for the operation.
+    method: The method identifier for the operation.
+    subscription_kind: A base.Subscription.Kind value describing the kind of
+      subscription to use for the operation.
+    timeout: A duration in seconds to pass as the timeout value for the
+      operation.
+    initial_metadata: An object to pass as the initial metadata for the
+      operation or None.
+    payload: An object to pass as a payload value for the operation or None.
+    completion: An object to pass as a completion value for the operation or
+      None.
+  """
+
+
+class OnAdvance(
+    collections.namedtuple(
+        'OnAdvance',
+        ('kind', 'initial_metadata', 'payload', 'completion', 'allowance'))):
+  """Describes action to be taken in a test in response to an advance call.
+
+  Attributes:
+    kind: A Kind value describing the overall kind of response.
+    initial_metadata: An initial metadata value to pass to a call of the advance
+      method of the operator under test. Only valid if kind is Kind.ADVANCE and
+      may be None.
+    payload: A payload value to pass to a call of the advance method of the
+      operator under test. Only valid if kind is Kind.ADVANCE and may be None.
+    completion: A base.Completion value to pass to a call of the advance method
+      of the operator under test. Only valid if kind is Kind.ADVANCE and may be
+      None.
+    allowance: An allowance value to pass to a call of the advance method of the
+      operator under test. Only valid if kind is Kind.ADVANCE and may be None.
+  """
+
+  @enum.unique
+  class Kind(enum.Enum):
+    ADVANCE = 'advance'
+    DEFECT = 'defect'
+    IDLE = 'idle'
+
+
+_DEFECT_ON_ADVANCE = OnAdvance(OnAdvance.Kind.DEFECT, None, None, None, None)
+_IDLE_ON_ADVANCE = OnAdvance(OnAdvance.Kind.IDLE, None, None, None, None)
+
+
+class Instruction(
+    collections.namedtuple(
+        'Instruction',
+        ('kind', 'advance_args', 'advance_kwargs', 'conclude_success',
+         'conclude_message', 'conclude_invocation_outcome_kind',
+         'conclude_service_outcome_kind',))):
+  """"""
+
+  @enum.unique
+  class Kind(enum.Enum):
+    ADVANCE = 'ADVANCE'
+    CANCEL = 'CANCEL'
+    CONCLUDE = 'CONCLUDE'
+
+
+class Controller(six.with_metaclass(abc.ABCMeta)):
+
+  @abc.abstractmethod
+  def failed(self, message):
+    """"""
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def serialize_request(self, request):
+    """"""
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def deserialize_request(self, serialized_request):
+    """"""
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def serialize_response(self, response):
+    """"""
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def deserialize_response(self, serialized_response):
+    """"""
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def invocation(self):
+    """"""
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def poll(self):
+    """"""
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def on_service_advance(
+      self, initial_metadata, payload, completion, allowance):
+    """"""
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def on_invocation_advance(
+      self, initial_metadata, payload, completion, allowance):
+    """"""
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def service_on_termination(self, outcome):
+    """"""
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def invocation_on_termination(self, outcome):
+    """"""
+    raise NotImplementedError()
+
+
+class ControllerCreator(six.with_metaclass(abc.ABCMeta)):
+
+  @abc.abstractmethod
+  def name(self):
+    """"""
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def controller(self, implementation, randomness):
+    """"""
+    raise NotImplementedError()
+
+
+class _Remainder(
+    collections.namedtuple(
+        '_Remainder',
+        ('invocation_payloads', 'service_payloads', 'invocation_completion',
+         'service_completion',))):
+  """Describes work remaining to be done in a portion of a test.
+
+  Attributes:
+    invocation_payloads: The number of payloads to be sent from the invocation
+      side of the operation to the service side of the operation.
+    service_payloads: The number of payloads to be sent from the service side of
+      the operation to the invocation side of the operation.
+    invocation_completion: Whether or not completion from the invocation side of
+      the operation should be indicated and has yet to be indicated.
+    service_completion: Whether or not completion from the service side of the
+      operation should be indicated and has yet to be indicated.
+  """
+
+
+class _SequenceController(Controller):
+
+  def __init__(self, sequence, implementation, randomness):
+    """Constructor.
+
+    Args:
+      sequence: A _sequence.Sequence describing the steps to be taken in the
+        test at a relatively high level.
+      implementation: A test_interfaces.Implementation encapsulating the
+        base interface implementation that is the system under test.
+      randomness: A random.Random instance for use in the test.
+    """
+    self._condition = threading.Condition()
+    self._sequence = sequence
+    self._implementation = implementation
+    self._randomness = randomness
+
+    self._until = None
+    self._remaining_elements = None
+    self._poll_next = None
+    self._message = None
+
+    self._state = _state.OperationState()
+    self._todo = None
+
+  # called with self._condition
+  def _failed(self, message):
+    self._message = message
+    self._condition.notify_all()
+
+  def _passed(self, invocation_outcome, service_outcome):
+    self._poll_next = Instruction(
+        Instruction.Kind.CONCLUDE, None, None, True, None, invocation_outcome,
+        service_outcome)
+    self._condition.notify_all()
+
+  def failed(self, message):
+    with self._condition:
+      self._failed(message)
+
+  def serialize_request(self, request):
+    return request + request
+
+  def deserialize_request(self, serialized_request):
+    return serialized_request[:len(serialized_request) // 2]
+
+  def serialize_response(self, response):
+    return response * 3
+
+  def deserialize_response(self, serialized_response):
+    return serialized_response[2 * len(serialized_response) // 3:]
+
+  def invocation(self):
+    with self._condition:
+      self._until = time.time() + self._sequence.maximum_duration
+      self._remaining_elements = list(self._sequence.elements)
+      if self._sequence.invocation.initial_metadata:
+        initial_metadata = self._implementation.invocation_initial_metadata()
+        self._state.invocation_initial_metadata_in_flight = initial_metadata
+      else:
+        initial_metadata = None
+      if self._sequence.invocation.payload:
+        payload = _create_payload(self._randomness)
+        self._state.invocation_payloads_in_flight.append(payload)
+      else:
+        payload = None
+      if self._sequence.invocation.complete:
+        completion = self._implementation.invocation_completion()
+        self._state.invocation_completion_in_flight = completion
+      else:
+        completion = None
+      return Invocation(
+          _GROUP, _METHOD, base.Subscription.Kind.FULL,
+          self._sequence.invocation.timeout, initial_metadata, payload,
+          completion)
+
+  def poll(self):
+    with self._condition:
+      while True:
+        if self._message is not None:
+          return Instruction(
+              Instruction.Kind.CONCLUDE, None, None, False, self._message, None,
+              None)
+        elif self._poll_next:
+          poll_next = self._poll_next
+          self._poll_next = None
+          return poll_next
+        elif self._until < time.time():
+          return Instruction(
+              Instruction.Kind.CONCLUDE, None, None, False,
+              'overran allotted time!', None, None)
+        else:
+          self._condition.wait(timeout=self._until-time.time())
+
+  def on_service_advance(
+      self, initial_metadata, payload, completion, allowance):
+    with self._condition:
+      message = _verify_service_advance_and_update_state(
+          initial_metadata, payload, completion, allowance, self._state,
+          self._implementation)
+      if message is not None:
+        self._failed(message)
+      if self._todo is not None:
+        raise ValueError('TODO!!!')
+      elif _anything_in_flight(self._state):
+        return _IDLE_ON_ADVANCE
+      elif self._remaining_elements:
+        element = self._remaining_elements.pop(0)
+        if element.kind is _sequence.Element.Kind.SERVICE_TRANSMISSION:
+          if element.transmission.initial_metadata:
+            initial_metadata = self._implementation.service_initial_metadata()
+            self._state.service_initial_metadata_in_flight = initial_metadata
+          else:
+            initial_metadata = None
+          if element.transmission.payload:
+            payload = _create_payload(self._randomness)
+            self._state.service_payloads_in_flight.append(payload)
+            self._state.service_side_service_allowance -= 1
+          else:
+            payload = None
+          if element.transmission.complete:
+            completion = self._implementation.service_completion()
+            self._state.service_completion_in_flight = completion
+          else:
+            completion = None
+          if (not self._state.invocation_completion_received and
+              0 <= self._state.service_side_invocation_allowance):
+            allowance = 1
+            self._state.service_side_invocation_allowance += 1
+            self._state.invocation_allowance_in_flight += 1
+          else:
+            allowance = None
+          return OnAdvance(
+              OnAdvance.Kind.ADVANCE, initial_metadata, payload, completion,
+              allowance)
+        else:
+          raise ValueError('TODO!!!')
+      else:
+        return _IDLE_ON_ADVANCE
+
+  def on_invocation_advance(
+      self, initial_metadata, payload, completion, allowance):
+    with self._condition:
+      message = _verify_invocation_advance_and_update_state(
+          initial_metadata, payload, completion, allowance, self._state,
+          self._implementation)
+      if message is not None:
+        self._failed(message)
+      if self._todo is not None:
+        raise ValueError('TODO!!!')
+      elif _anything_in_flight(self._state):
+        return _IDLE_ON_ADVANCE
+      elif self._remaining_elements:
+        element = self._remaining_elements.pop(0)
+        if element.kind is _sequence.Element.Kind.INVOCATION_TRANSMISSION:
+          if element.transmission.initial_metadata:
+            initial_metadata = self._implementation.invocation_initial_metadata()
+            self._state.invocation_initial_metadata_in_fight = initial_metadata
+          else:
+            initial_metadata = None
+          if element.transmission.payload:
+            payload = _create_payload(self._randomness)
+            self._state.invocation_payloads_in_flight.append(payload)
+            self._state.invocation_side_invocation_allowance -= 1
+          else:
+            payload = None
+          if element.transmission.complete:
+            completion = self._implementation.invocation_completion()
+            self._state.invocation_completion_in_flight = completion
+          else:
+            completion = None
+          if (not self._state.service_completion_received and
+              0 <= self._state.invocation_side_service_allowance):
+            allowance = 1
+            self._state.invocation_side_service_allowance += 1
+            self._state.service_allowance_in_flight += 1
+          else:
+            allowance = None
+          return OnAdvance(
+              OnAdvance.Kind.ADVANCE, initial_metadata, payload, completion,
+              allowance)
+        else:
+          raise ValueError('TODO!!!')
+      else:
+        return _IDLE_ON_ADVANCE
+
+  def service_on_termination(self, outcome):
+    with self._condition:
+      self._state.service_side_outcome = outcome
+      if self._todo is not None or self._remaining_elements:
+        self._failed('Premature service-side outcome %s!' % (outcome,))
+      elif outcome.kind is not self._sequence.outcome_kinds.service:
+        self._failed(
+            'Incorrect service-side outcome kind: %s should have been %s' % (
+                outcome.kind, self._sequence.outcome_kinds.service))
+      elif self._state.invocation_side_outcome is not None:
+        self._passed(self._state.invocation_side_outcome.kind, outcome.kind)
+
+  def invocation_on_termination(self, outcome):
+    with self._condition:
+      self._state.invocation_side_outcome = outcome
+      if self._todo is not None or self._remaining_elements:
+        self._failed('Premature invocation-side outcome %s!' % (outcome,))
+      elif outcome.kind is not self._sequence.outcome_kinds.invocation:
+        self._failed(
+            'Incorrect invocation-side outcome kind: %s should have been %s' % (
+                outcome.kind, self._sequence.outcome_kinds.invocation))
+      elif self._state.service_side_outcome is not None:
+        self._passed(outcome.kind, self._state.service_side_outcome.kind)
+
+
+class _SequenceControllerCreator(ControllerCreator):
+
+  def __init__(self, sequence):
+    self._sequence = sequence
+
+  def name(self):
+    return self._sequence.name
+
+  def controller(self, implementation, randomness):
+    return _SequenceController(self._sequence, implementation, randomness)
+
+
+CONTROLLER_CREATORS = tuple(
+    _SequenceControllerCreator(sequence) for sequence in _sequence.SEQUENCES)
diff --git a/src/python/grpcio_tests/tests/unit/framework/interfaces/base/_sequence.py b/src/python/grpcio_tests/tests/unit/framework/interfaces/base/_sequence.py
new file mode 100644
index 0000000000..571d0e1e63
--- /dev/null
+++ b/src/python/grpcio_tests/tests/unit/framework/interfaces/base/_sequence.py
@@ -0,0 +1,171 @@
+# 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.
+
+"""Part of the tests of the base interface of RPC Framework."""
+
+import collections
+import enum
+
+from grpc.framework.interfaces.base import base
+from tests.unit.framework.common import test_constants
+
+
+class Invocation(
+    collections.namedtuple(
+        'Invocation', ('timeout', 'initial_metadata', 'payload', 'complete',))):
+  """A recipe for operation invocation.
+
+  Attributes:
+    timeout: A duration in seconds to pass to the system under test as the
+      operation's timeout value.
+    initial_metadata: A boolean indicating whether or not to pass initial
+      metadata when invoking the operation.
+    payload: A boolean indicating whether or not to pass a payload when
+      invoking the operation.
+    complete: A boolean indicating whether or not to indicate completion of
+      transmissions from the invoking side of the operation when invoking the
+      operation.
+  """
+
+
+class Transmission(
+    collections.namedtuple(
+        'Transmission', ('initial_metadata', 'payload', 'complete',))):
+  """A recipe for a single transmission in an operation.
+
+  Attributes:
+    initial_metadata: A boolean indicating whether or not to pass initial
+      metadata as part of the transmission.
+    payload: A boolean indicating whether or not to pass a payload as part of
+      the transmission.
+    complete: A boolean indicating whether or not to indicate completion of
+      transmission from the transmitting side of the operation as part of the
+      transmission.
+  """
+
+
+class Intertransmission(
+    collections.namedtuple('Intertransmission', ('invocation', 'service',))):
+  """A recipe for multiple transmissions in an operation.
+
+  Attributes:
+    invocation: An integer describing the number of payloads to send from the
+      invocation side of the operation to the service side.
+    service: An integer describing the number of payloads to send from the
+      service side of the operation to the invocation side.
+  """
+
+
+class Element(collections.namedtuple('Element', ('kind', 'transmission',))):
+  """A sum type for steps to perform when testing an operation.
+
+  Attributes:
+    kind: A Kind value describing the kind of step to perform in the test.
+    transmission: Only valid for kinds Kind.INVOCATION_TRANSMISSION and
+      Kind.SERVICE_TRANSMISSION, a Transmission value describing the details of
+      the transmission to be made.
+  """
+
+  @enum.unique
+  class Kind(enum.Enum):
+    INVOCATION_TRANSMISSION = 'invocation transmission'
+    SERVICE_TRANSMISSION = 'service transmission'
+    INTERTRANSMISSION = 'intertransmission'
+    INVOCATION_CANCEL = 'invocation cancel'
+    SERVICE_CANCEL = 'service cancel'
+    INVOCATION_FAILURE = 'invocation failure'
+    SERVICE_FAILURE = 'service failure'
+
+
+class OutcomeKinds(
+    collections.namedtuple('Outcome', ('invocation', 'service',))):
+  """A description of the expected outcome of an operation test.
+
+  Attributes:
+    invocation: The base.Outcome.Kind value expected on the invocation side of
+      the operation.
+    service: The base.Outcome.Kind value expected on the service side of the
+      operation.
+  """
+
+
+class Sequence(
+    collections.namedtuple(
+        'Sequence',
+        ('name', 'maximum_duration', 'invocation', 'elements',
+         'outcome_kinds',))):
+  """Describes at a high level steps to perform in a test.
+
+  Attributes:
+    name: The string name of the sequence.
+    maximum_duration: A length of time in seconds to allow for the test before
+      declaring it to have failed.
+    invocation: An Invocation value describing how to invoke the operation
+      under test.
+    elements: A sequence of Element values describing at coarse granularity
+      actions to take during the operation under test.
+    outcome_kinds: An OutcomeKinds value describing the expected outcome kinds
+      of the test.
+  """
+
+_EASY = Sequence(
+    'Easy',
+    test_constants.TIME_ALLOWANCE,
+    Invocation(test_constants.LONG_TIMEOUT, True, True, True),
+    (
+        Element(
+            Element.Kind.SERVICE_TRANSMISSION, Transmission(True, True, True)),
+    ),
+    OutcomeKinds(base.Outcome.Kind.COMPLETED, base.Outcome.Kind.COMPLETED))
+
+_PEASY = Sequence(
+    'Peasy',
+    test_constants.TIME_ALLOWANCE,
+    Invocation(test_constants.LONG_TIMEOUT, True, True, False),
+    (
+        Element(
+            Element.Kind.SERVICE_TRANSMISSION, Transmission(True, True, False)),
+        Element(
+            Element.Kind.INVOCATION_TRANSMISSION,
+            Transmission(False, True, True)),
+        Element(
+            Element.Kind.SERVICE_TRANSMISSION, Transmission(False, True, True)),
+    ),
+    OutcomeKinds(base.Outcome.Kind.COMPLETED, base.Outcome.Kind.COMPLETED))
+
+
+# TODO(issue 2959): Finish this test suite. This tuple of sequences should
+# contain at least the values in the Cartesian product of (half-duplex,
+# full-duplex) * (zero payloads, one payload, test_constants.STREAM_LENGTH
+# payloads) * (completion, cancellation, expiration, programming defect in
+# servicer code).
+SEQUENCES = (
+    _EASY,
+    _PEASY,
+)
diff --git a/src/python/grpcio_tests/tests/unit/framework/interfaces/base/_state.py b/src/python/grpcio_tests/tests/unit/framework/interfaces/base/_state.py
new file mode 100644
index 0000000000..21cf33aeb6
--- /dev/null
+++ b/src/python/grpcio_tests/tests/unit/framework/interfaces/base/_state.py
@@ -0,0 +1,55 @@
+# 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.
+
+"""Part of the tests of the base interface of RPC Framework."""
+
+
+class OperationState(object):
+
+  def __init__(self):
+    self.invocation_initial_metadata_in_flight = None
+    self.invocation_initial_metadata_received = False
+    self.invocation_payloads_in_flight = []
+    self.invocation_payloads_received = 0
+    self.invocation_completion_in_flight = None
+    self.invocation_completion_received = False
+    self.service_initial_metadata_in_flight = None
+    self.service_initial_metadata_received = False
+    self.service_payloads_in_flight = []
+    self.service_payloads_received = 0
+    self.service_completion_in_flight = None
+    self.service_completion_received = False
+    self.invocation_side_invocation_allowance = 1
+    self.invocation_side_service_allowance = 1
+    self.service_side_invocation_allowance = 1
+    self.service_side_service_allowance = 1
+    self.invocation_allowance_in_flight = 0
+    self.service_allowance_in_flight = 0
+    self.invocation_side_outcome = None
+    self.service_side_outcome = None
diff --git a/src/python/grpcio_tests/tests/unit/framework/interfaces/base/test_cases.py b/src/python/grpcio_tests/tests/unit/framework/interfaces/base/test_cases.py
new file mode 100644
index 0000000000..5d16bf98be
--- /dev/null
+++ b/src/python/grpcio_tests/tests/unit/framework/interfaces/base/test_cases.py
@@ -0,0 +1,279 @@
+# 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.
+
+"""Tests of the base interface of RPC Framework."""
+
+from __future__ import division
+
+import logging
+import random
+import threading
+import time
+import unittest
+
+from grpc.framework.foundation import logging_pool
+from grpc.framework.interfaces.base import base
+from grpc.framework.interfaces.base import utilities
+from tests.unit.framework.common import test_constants
+from tests.unit.framework.interfaces.base import _control
+from tests.unit.framework.interfaces.base import test_interfaces
+
+_SYNCHRONICITY_VARIATION = (('Sync', False), ('Async', True))
+
+_EMPTY_OUTCOME_KIND_DICT = {
+    outcome_kind: 0 for outcome_kind in base.Outcome.Kind}
+
+
+class _Serialization(test_interfaces.Serialization):
+
+  def serialize_request(self, request):
+    return request + request
+
+  def deserialize_request(self, serialized_request):
+    return serialized_request[:len(serialized_request) // 2]
+
+  def serialize_response(self, response):
+    return response * 3
+
+  def deserialize_response(self, serialized_response):
+    return serialized_response[2 * len(serialized_response) // 3:]
+
+
+def _advance(quadruples, operator, controller):
+  try:
+    for quadruple in quadruples:
+      operator.advance(
+          initial_metadata=quadruple[0], payload=quadruple[1],
+          completion=quadruple[2], allowance=quadruple[3])
+  except Exception as e:  # pylint: disable=broad-except
+    controller.failed('Exception on advance: %e' % e)
+
+
+class _Operator(base.Operator):
+
+  def __init__(self, controller, on_advance, pool, operator_under_test):
+    self._condition = threading.Condition()
+    self._controller = controller
+    self._on_advance = on_advance
+    self._pool = pool
+    self._operator_under_test = operator_under_test
+    self._pending_advances = []
+
+  def set_operator_under_test(self, operator_under_test):
+    with self._condition:
+      self._operator_under_test = operator_under_test
+      pent_advances = self._pending_advances
+      self._pending_advances = []
+      pool = self._pool
+      controller = self._controller
+
+    if pool is None:
+      _advance(pent_advances, operator_under_test, controller)
+    else:
+      pool.submit(_advance, pent_advances, operator_under_test, controller)
+
+  def advance(
+      self, initial_metadata=None, payload=None, completion=None,
+      allowance=None):
+    on_advance = self._on_advance(
+        initial_metadata, payload, completion, allowance)
+    if on_advance.kind is _control.OnAdvance.Kind.ADVANCE:
+      with self._condition:
+        pool = self._pool
+        operator_under_test = self._operator_under_test
+        controller = self._controller
+
+      quadruple = (
+          on_advance.initial_metadata, on_advance.payload,
+          on_advance.completion, on_advance.allowance)
+      if pool is None:
+        _advance((quadruple,), operator_under_test, controller)
+      else:
+        pool.submit(_advance, (quadruple,), operator_under_test, controller)
+    elif on_advance.kind is _control.OnAdvance.Kind.DEFECT:
+      raise ValueError(
+          'Deliberately raised exception from Operator.advance (in a test)!')
+
+
+class _ProtocolReceiver(base.ProtocolReceiver):
+
+  def __init__(self):
+    self._condition = threading.Condition()
+    self._contexts = []
+
+  def context(self, protocol_context):
+    with self._condition:
+      self._contexts.append(protocol_context)
+
+
+class _Servicer(base.Servicer):
+  """A base.Servicer with instrumented for testing."""
+
+  def __init__(self, group, method, controllers, pool):
+    self._condition = threading.Condition()
+    self._group = group
+    self._method = method
+    self._pool = pool
+    self._controllers = list(controllers)
+
+  def service(self, group, method, context, output_operator):
+    with self._condition:
+      controller = self._controllers.pop(0)
+      if group != self._group or method != self._method:
+        controller.fail(
+            '%s != %s or %s != %s' % (group, self._group, method, self._method))
+        raise base.NoSuchMethodError(None, None)
+      else:
+        operator = _Operator(
+            controller, controller.on_service_advance, self._pool,
+            output_operator)
+        outcome = context.add_termination_callback(
+            controller.service_on_termination)
+        if outcome is not None:
+          controller.service_on_termination(outcome)
+        return utilities.full_subscription(operator, _ProtocolReceiver())
+
+
+class _OperationTest(unittest.TestCase):
+
+  def setUp(self):
+    if self._synchronicity_variation:
+      self._pool = logging_pool.pool(test_constants.POOL_SIZE)
+    else:
+      self._pool = None
+    self._controller = self._controller_creator.controller(
+        self._implementation, self._randomness)
+
+  def tearDown(self):
+    if self._synchronicity_variation:
+      self._pool.shutdown(wait=True)
+    else:
+      self._pool = None
+
+  def test_operation(self):
+    invocation = self._controller.invocation()
+    if invocation.subscription_kind is base.Subscription.Kind.FULL:
+      test_operator = _Operator(
+          self._controller, self._controller.on_invocation_advance,
+          self._pool, None)
+      subscription = utilities.full_subscription(
+          test_operator, _ProtocolReceiver())
+    else:
+      # TODO(nathaniel): support and test other subscription kinds.
+      self.fail('Non-full subscriptions not yet supported!')
+
+    servicer = _Servicer(
+        invocation.group, invocation.method, (self._controller,), self._pool)
+
+    invocation_end, service_end, memo = self._implementation.instantiate(
+        {(invocation.group, invocation.method): _Serialization()}, servicer)
+
+    try:
+      invocation_end.start()
+      service_end.start()
+      operation_context, operator_under_test = invocation_end.operate(
+          invocation.group, invocation.method, subscription, invocation.timeout,
+          initial_metadata=invocation.initial_metadata, payload=invocation.payload,
+          completion=invocation.completion)
+      test_operator.set_operator_under_test(operator_under_test)
+      outcome = operation_context.add_termination_callback(
+          self._controller.invocation_on_termination)
+      if outcome is not None:
+        self._controller.invocation_on_termination(outcome)
+    except Exception as e:  # pylint: disable=broad-except
+      self._controller.failed('Exception on invocation: %s' % e)
+      self.fail(e)
+
+    while True:
+      instruction = self._controller.poll()
+      if instruction.kind is _control.Instruction.Kind.ADVANCE:
+        try:
+          test_operator.advance(
+              *instruction.advance_args, **instruction.advance_kwargs)
+        except Exception as e:  # pylint: disable=broad-except
+          self._controller.failed('Exception on instructed advance: %s' % e)
+      elif instruction.kind is _control.Instruction.Kind.CANCEL:
+        try:
+          operation_context.cancel()
+        except Exception as e:  # pylint: disable=broad-except
+          self._controller.failed('Exception on cancel: %s' % e)
+      elif instruction.kind is _control.Instruction.Kind.CONCLUDE:
+        break
+
+    invocation_stop_event = invocation_end.stop(0)
+    service_stop_event = service_end.stop(0)
+    invocation_stop_event.wait()
+    service_stop_event.wait()
+    invocation_stats = invocation_end.operation_stats()
+    service_stats = service_end.operation_stats()
+
+    self._implementation.destantiate(memo)
+
+    self.assertTrue(
+        instruction.conclude_success, msg=instruction.conclude_message)
+
+    expected_invocation_stats = dict(_EMPTY_OUTCOME_KIND_DICT)
+    expected_invocation_stats[
+        instruction.conclude_invocation_outcome_kind] += 1
+    self.assertDictEqual(expected_invocation_stats, invocation_stats)
+    expected_service_stats = dict(_EMPTY_OUTCOME_KIND_DICT)
+    expected_service_stats[instruction.conclude_service_outcome_kind] += 1
+    self.assertDictEqual(expected_service_stats, service_stats)
+
+
+def test_cases(implementation):
+  """Creates unittest.TestCase classes for a given Base implementation.
+
+  Args:
+    implementation: A test_interfaces.Implementation specifying creation and
+      destruction of the Base implementation under test.
+
+  Returns:
+    A sequence of subclasses of unittest.TestCase defining tests of the
+      specified Base layer implementation.
+  """
+  random_seed = hash(time.time())
+  logging.warning('Random seed for this execution: %s', random_seed)
+  randomness = random.Random(x=random_seed)
+
+  test_case_classes = []
+  for synchronicity_variation in _SYNCHRONICITY_VARIATION:
+    for controller_creator in _control.CONTROLLER_CREATORS:
+      name = ''.join(
+          (synchronicity_variation[0], controller_creator.name(), 'Test',))
+      test_case_classes.append(
+          type(name, (_OperationTest,),
+               {'_implementation': implementation,
+                '_randomness': randomness,
+                '_synchronicity_variation': synchronicity_variation[1],
+                '_controller_creator': controller_creator,
+                '__module__': implementation.__module__,
+               }))
+
+  return test_case_classes
diff --git a/src/python/grpcio_tests/tests/unit/framework/interfaces/base/test_interfaces.py b/src/python/grpcio_tests/tests/unit/framework/interfaces/base/test_interfaces.py
new file mode 100644
index 0000000000..5eba475ba8
--- /dev/null
+++ b/src/python/grpcio_tests/tests/unit/framework/interfaces/base/test_interfaces.py
@@ -0,0 +1,186 @@
+# 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.
+
+"""Interfaces used in tests of implementations of the Base layer."""
+
+import abc
+
+import six
+
+from grpc.framework.interfaces.base import base  # pylint: disable=unused-import
+
+
+class Serialization(six.with_metaclass(abc.ABCMeta)):
+  """Specifies serialization and deserialization of test payloads."""
+
+  def serialize_request(self, request):
+    """Serializes a request value used in a test.
+
+    Args:
+      request: A request value created by a test.
+
+    Returns:
+      A bytestring that is the serialization of the given request.
+    """
+    raise NotImplementedError()
+
+  def deserialize_request(self, serialized_request):
+    """Deserializes a request value used in a test.
+
+    Args:
+      serialized_request: A bytestring that is the serialization of some request
+        used in a test.
+
+    Returns:
+      The request value encoded by the given bytestring.
+    """
+    raise NotImplementedError()
+
+  def serialize_response(self, response):
+    """Serializes a response value used in a test.
+
+    Args:
+      response: A response value created by a test.
+
+    Returns:
+      A bytestring that is the serialization of the given response.
+    """
+    raise NotImplementedError()
+
+  def deserialize_response(self, serialized_response):
+    """Deserializes a response value used in a test.
+
+    Args:
+      serialized_response: A bytestring that is the serialization of some
+        response used in a test.
+
+    Returns:
+      The response value encoded by the given bytestring.
+    """
+    raise NotImplementedError()
+
+
+class Implementation(six.with_metaclass(abc.ABCMeta)):
+  """Specifies an implementation of the Base layer."""
+
+  @abc.abstractmethod
+  def instantiate(self, serializations, servicer):
+    """Instantiates the Base layer implementation to be used in a test.
+
+    Args:
+      serializations: A dict from group-method pair to Serialization object
+        specifying how to serialize and deserialize payload values used in the
+        test.
+      servicer: A base.Servicer object to be called to service RPCs made during
+        the test.
+
+    Returns:
+      A sequence of length three the first element of which is a
+        base.End to be used to invoke RPCs, the second element of which is a
+        base.End to be used to service invoked RPCs, and the third element of
+        which is an arbitrary memo object to be kept and passed to destantiate
+        at the conclusion of the test.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def destantiate(self, memo):
+    """Destroys the Base layer implementation under test.
+
+    Args:
+      memo: The object from the third position of the return value of a call to
+        instantiate.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def invocation_initial_metadata(self):
+    """Provides an operation's invocation-side initial metadata.
+
+    Returns:
+      A value to use for an operation's invocation-side initial metadata, or
+        None.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def service_initial_metadata(self):
+    """Provides an operation's service-side initial metadata.
+
+    Returns:
+      A value to use for an operation's service-side initial metadata, or
+        None.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def invocation_completion(self):
+    """Provides an operation's invocation-side completion.
+
+    Returns:
+      A base.Completion to use for an operation's invocation-side completion.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def service_completion(self):
+    """Provides an operation's service-side completion.
+
+    Returns:
+      A base.Completion to use for an operation's service-side completion.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def metadata_transmitted(self, original_metadata, transmitted_metadata):
+    """Identifies whether or not metadata was properly transmitted.
+
+    Args:
+      original_metadata: A metadata value passed to the system under test.
+      transmitted_metadata: The same metadata value after having been
+        transmitted through the system under test.
+
+    Returns:
+      Whether or not the metadata was properly transmitted.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def completion_transmitted(self, original_completion, transmitted_completion):
+    """Identifies whether or not a base.Completion was properly transmitted.
+
+    Args:
+      original_completion: A base.Completion passed to the system under test.
+      transmitted_completion: The same completion value after having been
+        transmitted through the system under test.
+
+    Returns:
+      Whether or not the completion was properly transmitted.
+    """
+    raise NotImplementedError()
diff --git a/src/python/grpcio_tests/tests/unit/framework/interfaces/face/_3069_test_constant.py b/src/python/grpcio_tests/tests/unit/framework/interfaces/face/_3069_test_constant.py
new file mode 100644
index 0000000000..1ea356c0bf
--- /dev/null
+++ b/src/python/grpcio_tests/tests/unit/framework/interfaces/face/_3069_test_constant.py
@@ -0,0 +1,37 @@
+# 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.
+
+"""A test constant working around issue 3069."""
+
+# test_constants is referenced from specification in this module.
+from tests.unit.framework.common import test_constants  # pylint: disable=unused-import
+
+# TODO(issue 3069): Replace uses of this constant with
+# test_constants.SHORT_TIMEOUT.
+REALLY_SHORT_TIMEOUT = 0.1
diff --git a/src/python/grpcio_tests/tests/unit/framework/interfaces/face/__init__.py b/src/python/grpcio_tests/tests/unit/framework/interfaces/face/__init__.py
new file mode 100644
index 0000000000..7086519106
--- /dev/null
+++ b/src/python/grpcio_tests/tests/unit/framework/interfaces/face/__init__.py
@@ -0,0 +1,30 @@
+# 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/framework/interfaces/face/_blocking_invocation_inline_service.py b/src/python/grpcio_tests/tests/unit/framework/interfaces/face/_blocking_invocation_inline_service.py
new file mode 100644
index 0000000000..e338aaa396
--- /dev/null
+++ b/src/python/grpcio_tests/tests/unit/framework/interfaces/face/_blocking_invocation_inline_service.py
@@ -0,0 +1,295 @@
+# 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.
+
+"""Test code for the Face layer of RPC Framework."""
+
+from __future__ import division
+
+import abc
+import itertools
+import unittest
+from concurrent import futures
+
+import six
+
+# test_interfaces is referenced from specification in this module.
+from grpc.framework.foundation import logging_pool
+from grpc.framework.interfaces.face import face
+from tests.unit.framework.common import test_constants
+from tests.unit.framework.common import test_control
+from tests.unit.framework.common import test_coverage
+from tests.unit.framework.interfaces.face import _3069_test_constant
+from tests.unit.framework.interfaces.face import _digest
+from tests.unit.framework.interfaces.face import _stock_service
+from tests.unit.framework.interfaces.face import test_interfaces  # pylint: disable=unused-import
+
+
+class TestCase(six.with_metaclass(abc.ABCMeta, test_coverage.Coverage, unittest.TestCase)):
+  """A test of the Face layer of RPC Framework.
+
+  Concrete subclasses must have an "implementation" attribute of type
+  test_interfaces.Implementation and an "invoker_constructor" attribute of type
+  _invocation.InvokerConstructor.
+  """
+
+  NAME = 'BlockingInvocationInlineServiceTest'
+
+  def setUp(self):
+    """See unittest.TestCase.setUp for full specification.
+
+    Overriding implementations must call this implementation.
+    """
+    self._control = test_control.PauseFailControl()
+    self._digest = _digest.digest(
+        _stock_service.STOCK_TEST_SERVICE, self._control, None)
+
+    generic_stub, dynamic_stubs, self._memo = self.implementation.instantiate(
+        self._digest.methods, self._digest.inline_method_implementations, None)
+    self._invoker = self.invoker_constructor.construct_invoker(
+        generic_stub, dynamic_stubs, self._digest.methods)
+
+  def tearDown(self):
+    """See unittest.TestCase.tearDown for full specification.
+
+    Overriding implementations must call this implementation.
+    """
+    self._invoker = None
+    self.implementation.destantiate(self._memo)
+
+  def testSuccessfulUnaryRequestUnaryResponse(self):
+    for (group, method), test_messages_sequence in (
+        six.iteritems(self._digest.unary_unary_messages_sequences)):
+      for test_messages in test_messages_sequence:
+        request = test_messages.request()
+
+        response, call = self._invoker.blocking(group, method)(
+            request, test_constants.LONG_TIMEOUT, with_call=True)
+
+        test_messages.verify(request, response, self)
+
+  def testSuccessfulUnaryRequestStreamResponse(self):
+    for (group, method), test_messages_sequence in (
+        six.iteritems(self._digest.unary_stream_messages_sequences)):
+      for test_messages in test_messages_sequence:
+        request = test_messages.request()
+
+        response_iterator = self._invoker.blocking(group, method)(
+            request, test_constants.LONG_TIMEOUT)
+        responses = list(response_iterator)
+
+        test_messages.verify(request, responses, self)
+
+  def testSuccessfulStreamRequestUnaryResponse(self):
+    for (group, method), test_messages_sequence in (
+        six.iteritems(self._digest.stream_unary_messages_sequences)):
+      for test_messages in test_messages_sequence:
+        requests = test_messages.requests()
+
+        response, call = self._invoker.blocking(group, method)(
+            iter(requests), test_constants.LONG_TIMEOUT, with_call=True)
+
+        test_messages.verify(requests, response, self)
+
+  def testSuccessfulStreamRequestStreamResponse(self):
+    for (group, method), test_messages_sequence in (
+        six.iteritems(self._digest.stream_stream_messages_sequences)):
+      for test_messages in test_messages_sequence:
+        requests = test_messages.requests()
+
+        response_iterator = self._invoker.blocking(group, method)(
+            iter(requests), test_constants.LONG_TIMEOUT)
+        responses = list(response_iterator)
+
+        test_messages.verify(requests, responses, self)
+
+  def testSequentialInvocations(self):
+    for (group, method), test_messages_sequence in (
+        six.iteritems(self._digest.unary_unary_messages_sequences)):
+      for test_messages in test_messages_sequence:
+        first_request = test_messages.request()
+        second_request = test_messages.request()
+
+        first_response = self._invoker.blocking(group, method)(
+            first_request, test_constants.LONG_TIMEOUT)
+
+        test_messages.verify(first_request, first_response, self)
+
+        second_response = self._invoker.blocking(group, method)(
+            second_request, test_constants.LONG_TIMEOUT)
+
+        test_messages.verify(second_request, second_response, self)
+
+  def testParallelInvocations(self):
+    pool = logging_pool.pool(test_constants.THREAD_CONCURRENCY)
+    for (group, method), test_messages_sequence in (
+        six.iteritems(self._digest.unary_unary_messages_sequences)):
+      for test_messages in test_messages_sequence:
+        requests = []
+        response_futures = []
+        for _ in range(test_constants.THREAD_CONCURRENCY):
+          request = test_messages.request()
+          response_future = pool.submit(
+              self._invoker.blocking(group, method), request,
+              test_constants.LONG_TIMEOUT)
+          requests.append(request)
+          response_futures.append(response_future)
+
+        responses = [
+            response_future.result() for response_future in response_futures]
+
+        for request, response in zip(requests, responses):
+          test_messages.verify(request, response, self)
+    pool.shutdown(wait=True)
+
+  def testWaitingForSomeButNotAllParallelInvocations(self):
+    pool = logging_pool.pool(test_constants.THREAD_CONCURRENCY)
+    for (group, method), test_messages_sequence in (
+        six.iteritems(self._digest.unary_unary_messages_sequences)):
+      for test_messages in test_messages_sequence:
+        requests = []
+        response_futures_to_indices = {}
+        for index in range(test_constants.THREAD_CONCURRENCY):
+          request = test_messages.request()
+          response_future = pool.submit(
+              self._invoker.blocking(group, method), request,
+              test_constants.LONG_TIMEOUT)
+          requests.append(request)
+          response_futures_to_indices[response_future] = index
+
+        some_completed_response_futures_iterator = itertools.islice(
+            futures.as_completed(response_futures_to_indices),
+            test_constants.THREAD_CONCURRENCY // 2)
+        for response_future in some_completed_response_futures_iterator:
+          index = response_futures_to_indices[response_future]
+          test_messages.verify(requests[index], response_future.result(), self)
+    pool.shutdown(wait=True)
+
+  @unittest.skip('Cancellation impossible with blocking control flow!')
+  def testCancelledUnaryRequestUnaryResponse(self):
+    raise NotImplementedError()
+
+  @unittest.skip('Cancellation impossible with blocking control flow!')
+  def testCancelledUnaryRequestStreamResponse(self):
+    raise NotImplementedError()
+
+  @unittest.skip('Cancellation impossible with blocking control flow!')
+  def testCancelledStreamRequestUnaryResponse(self):
+    raise NotImplementedError()
+
+  @unittest.skip('Cancellation impossible with blocking control flow!')
+  def testCancelledStreamRequestStreamResponse(self):
+    raise NotImplementedError()
+
+  def testExpiredUnaryRequestUnaryResponse(self):
+    for (group, method), test_messages_sequence in (
+        six.iteritems(self._digest.unary_unary_messages_sequences)):
+      for test_messages in test_messages_sequence:
+        request = test_messages.request()
+
+        with self._control.pause(), self.assertRaises(
+            face.ExpirationError):
+          self._invoker.blocking(group, method)(
+              request, _3069_test_constant.REALLY_SHORT_TIMEOUT)
+
+  def testExpiredUnaryRequestStreamResponse(self):
+    for (group, method), test_messages_sequence in (
+        six.iteritems(self._digest.unary_stream_messages_sequences)):
+      for test_messages in test_messages_sequence:
+        request = test_messages.request()
+
+        with self._control.pause(), self.assertRaises(
+            face.ExpirationError):
+          response_iterator = self._invoker.blocking(group, method)(
+              request, _3069_test_constant.REALLY_SHORT_TIMEOUT)
+          list(response_iterator)
+
+  def testExpiredStreamRequestUnaryResponse(self):
+    for (group, method), test_messages_sequence in (
+        six.iteritems(self._digest.stream_unary_messages_sequences)):
+      for test_messages in test_messages_sequence:
+        requests = test_messages.requests()
+
+        with self._control.pause(), self.assertRaises(
+            face.ExpirationError):
+          self._invoker.blocking(group, method)(
+              iter(requests), _3069_test_constant.REALLY_SHORT_TIMEOUT)
+
+  def testExpiredStreamRequestStreamResponse(self):
+    for (group, method), test_messages_sequence in (
+        six.iteritems(self._digest.stream_stream_messages_sequences)):
+      for test_messages in test_messages_sequence:
+        requests = test_messages.requests()
+
+        with self._control.pause(), self.assertRaises(
+            face.ExpirationError):
+          response_iterator = self._invoker.blocking(group, method)(
+              iter(requests), _3069_test_constant.REALLY_SHORT_TIMEOUT)
+          list(response_iterator)
+
+  def testFailedUnaryRequestUnaryResponse(self):
+    for (group, method), test_messages_sequence in (
+        six.iteritems(self._digest.unary_unary_messages_sequences)):
+      for test_messages in test_messages_sequence:
+        request = test_messages.request()
+
+        with self._control.fail(), self.assertRaises(face.RemoteError):
+          self._invoker.blocking(group, method)(
+              request, test_constants.LONG_TIMEOUT)
+
+  def testFailedUnaryRequestStreamResponse(self):
+    for (group, method), test_messages_sequence in (
+        six.iteritems(self._digest.unary_stream_messages_sequences)):
+      for test_messages in test_messages_sequence:
+        request = test_messages.request()
+
+        with self._control.fail(), self.assertRaises(face.RemoteError):
+          response_iterator = self._invoker.blocking(group, method)(
+              request, test_constants.LONG_TIMEOUT)
+          list(response_iterator)
+
+  def testFailedStreamRequestUnaryResponse(self):
+    for (group, method), test_messages_sequence in (
+        six.iteritems(self._digest.stream_unary_messages_sequences)):
+      for test_messages in test_messages_sequence:
+        requests = test_messages.requests()
+
+        with self._control.fail(), self.assertRaises(face.RemoteError):
+          self._invoker.blocking(group, method)(
+              iter(requests), test_constants.LONG_TIMEOUT)
+
+  def testFailedStreamRequestStreamResponse(self):
+    for (group, method), test_messages_sequence in (
+        six.iteritems(self._digest.stream_stream_messages_sequences)):
+      for test_messages in test_messages_sequence:
+        requests = test_messages.requests()
+
+        with self._control.fail(), self.assertRaises(face.RemoteError):
+          response_iterator = self._invoker.blocking(group, method)(
+              iter(requests), test_constants.LONG_TIMEOUT)
+          list(response_iterator)
diff --git a/src/python/grpcio_tests/tests/unit/framework/interfaces/face/_digest.py b/src/python/grpcio_tests/tests/unit/framework/interfaces/face/_digest.py
new file mode 100644
index 0000000000..f0befb0b27
--- /dev/null
+++ b/src/python/grpcio_tests/tests/unit/framework/interfaces/face/_digest.py
@@ -0,0 +1,446 @@
+# 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.
+
+"""Code for making a service.TestService more amenable to use in tests."""
+
+import collections
+import threading
+
+import six
+
+# test_control, _service, and test_interfaces are referenced from specification
+# in this module.
+from grpc.framework.common import cardinality
+from grpc.framework.common import style
+from grpc.framework.foundation import stream
+from grpc.framework.foundation import stream_util
+from grpc.framework.interfaces.face import face
+from tests.unit.framework.common import test_control  # pylint: disable=unused-import
+from tests.unit.framework.interfaces.face import _service  # pylint: disable=unused-import
+from tests.unit.framework.interfaces.face import test_interfaces  # pylint: disable=unused-import
+
+_IDENTITY = lambda x: x
+
+
+class TestServiceDigest(
+    collections.namedtuple(
+        'TestServiceDigest',
+        ('methods',
+         'inline_method_implementations',
+         'event_method_implementations',
+         'multi_method_implementation',
+         'unary_unary_messages_sequences',
+         'unary_stream_messages_sequences',
+         'stream_unary_messages_sequences',
+         'stream_stream_messages_sequences',))):
+  """A transformation of a service.TestService.
+
+  Attributes:
+    methods: A dict from method group-name pair to test_interfaces.Method object
+      describing the RPC methods that may be called during the test.
+    inline_method_implementations: A dict from method group-name pair to
+      face.MethodImplementation object to be used in tests of in-line calls to
+      behaviors under test.
+    event_method_implementations: A dict from method group-name pair to
+      face.MethodImplementation object to be used in tests of event-driven calls
+      to behaviors under test.
+    multi_method_implementation: A face.MultiMethodImplementation to be used in
+      tests of generic calls to behaviors under test.
+    unary_unary_messages_sequences: A dict from method group-name pair to
+      sequence of service.UnaryUnaryTestMessages objects to be used to test the
+      identified method.
+    unary_stream_messages_sequences: A dict from method group-name pair to
+      sequence of service.UnaryStreamTestMessages objects to be used to test the
+      identified method.
+    stream_unary_messages_sequences: A dict from method group-name pair to
+      sequence of service.StreamUnaryTestMessages objects to be used to test the
+      identified method.
+    stream_stream_messages_sequences: A dict from method group-name pair to
+      sequence of service.StreamStreamTestMessages objects to be used to test
+      the identified method.
+  """
+
+
+class _BufferingConsumer(stream.Consumer):
+  """A trivial Consumer that dumps what it consumes in a user-mutable buffer."""
+
+  def __init__(self):
+    self.consumed = []
+    self.terminated = False
+
+  def consume(self, value):
+    self.consumed.append(value)
+
+  def terminate(self):
+    self.terminated = True
+
+  def consume_and_terminate(self, value):
+    self.consumed.append(value)
+    self.terminated = True
+
+
+class _InlineUnaryUnaryMethod(face.MethodImplementation):
+
+  def __init__(self, unary_unary_test_method, control):
+    self._test_method = unary_unary_test_method
+    self._control = control
+
+    self.cardinality = cardinality.Cardinality.UNARY_UNARY
+    self.style = style.Service.INLINE
+
+  def unary_unary_inline(self, request, context):
+    response_list = []
+    self._test_method.service(
+        request, response_list.append, context, self._control)
+    return response_list.pop(0)
+
+
+class _EventUnaryUnaryMethod(face.MethodImplementation):
+
+  def __init__(self, unary_unary_test_method, control, pool):
+    self._test_method = unary_unary_test_method
+    self._control = control
+    self._pool = pool
+
+    self.cardinality = cardinality.Cardinality.UNARY_UNARY
+    self.style = style.Service.EVENT
+
+  def unary_unary_event(self, request, response_callback, context):
+    if self._pool is None:
+      self._test_method.service(
+          request, response_callback, context, self._control)
+    else:
+      self._pool.submit(
+          self._test_method.service, request, response_callback, context,
+          self._control)
+
+
+class _InlineUnaryStreamMethod(face.MethodImplementation):
+
+  def __init__(self, unary_stream_test_method, control):
+    self._test_method = unary_stream_test_method
+    self._control = control
+
+    self.cardinality = cardinality.Cardinality.UNARY_STREAM
+    self.style = style.Service.INLINE
+
+  def unary_stream_inline(self, request, context):
+    response_consumer = _BufferingConsumer()
+    self._test_method.service(
+        request, response_consumer, context, self._control)
+    for response in response_consumer.consumed:
+      yield response
+
+
+class _EventUnaryStreamMethod(face.MethodImplementation):
+
+  def __init__(self, unary_stream_test_method, control, pool):
+    self._test_method = unary_stream_test_method
+    self._control = control
+    self._pool = pool
+
+    self.cardinality = cardinality.Cardinality.UNARY_STREAM
+    self.style = style.Service.EVENT
+
+  def unary_stream_event(self, request, response_consumer, context):
+    if self._pool is None:
+      self._test_method.service(
+          request, response_consumer, context, self._control)
+    else:
+      self._pool.submit(
+          self._test_method.service, request, response_consumer, context,
+          self._control)
+
+
+class _InlineStreamUnaryMethod(face.MethodImplementation):
+
+  def __init__(self, stream_unary_test_method, control):
+    self._test_method = stream_unary_test_method
+    self._control = control
+
+    self.cardinality = cardinality.Cardinality.STREAM_UNARY
+    self.style = style.Service.INLINE
+
+  def stream_unary_inline(self, request_iterator, context):
+    response_list = []
+    request_consumer = self._test_method.service(
+        response_list.append, context, self._control)
+    for request in request_iterator:
+      request_consumer.consume(request)
+    request_consumer.terminate()
+    return response_list.pop(0)
+
+
+class _EventStreamUnaryMethod(face.MethodImplementation):
+
+  def __init__(self, stream_unary_test_method, control, pool):
+    self._test_method = stream_unary_test_method
+    self._control = control
+    self._pool = pool
+
+    self.cardinality = cardinality.Cardinality.STREAM_UNARY
+    self.style = style.Service.EVENT
+
+  def stream_unary_event(self, response_callback, context):
+    request_consumer = self._test_method.service(
+        response_callback, context, self._control)
+    if self._pool is None:
+      return request_consumer
+    else:
+      return stream_util.ThreadSwitchingConsumer(request_consumer, self._pool)
+
+
+class _InlineStreamStreamMethod(face.MethodImplementation):
+
+  def __init__(self, stream_stream_test_method, control):
+    self._test_method = stream_stream_test_method
+    self._control = control
+
+    self.cardinality = cardinality.Cardinality.STREAM_STREAM
+    self.style = style.Service.INLINE
+
+  def stream_stream_inline(self, request_iterator, context):
+    response_consumer = _BufferingConsumer()
+    request_consumer = self._test_method.service(
+        response_consumer, context, self._control)
+
+    for request in request_iterator:
+      request_consumer.consume(request)
+      while response_consumer.consumed:
+        yield response_consumer.consumed.pop(0)
+    response_consumer.terminate()
+
+
+class _EventStreamStreamMethod(face.MethodImplementation):
+
+  def __init__(self, stream_stream_test_method, control, pool):
+    self._test_method = stream_stream_test_method
+    self._control = control
+    self._pool = pool
+
+    self.cardinality = cardinality.Cardinality.STREAM_STREAM
+    self.style = style.Service.EVENT
+
+  def stream_stream_event(self, response_consumer, context):
+    request_consumer = self._test_method.service(
+        response_consumer, context, self._control)
+    if self._pool is None:
+      return request_consumer
+    else:
+      return stream_util.ThreadSwitchingConsumer(request_consumer, self._pool)
+
+
+class _UnaryConsumer(stream.Consumer):
+  """A Consumer that only allows consumption of exactly one value."""
+
+  def __init__(self, action):
+    self._lock = threading.Lock()
+    self._action = action
+    self._consumed = False
+    self._terminated = False
+
+  def consume(self, value):
+    with self._lock:
+      if self._consumed:
+        raise ValueError('Unary consumer already consumed!')
+      elif self._terminated:
+        raise ValueError('Unary consumer already terminated!')
+      else:
+        self._consumed = True
+
+    self._action(value)
+
+  def terminate(self):
+    with self._lock:
+      if not self._consumed:
+        raise ValueError('Unary consumer hasn\'t yet consumed!')
+      elif self._terminated:
+        raise ValueError('Unary consumer already terminated!')
+      else:
+        self._terminated = True
+
+  def consume_and_terminate(self, value):
+    with self._lock:
+      if self._consumed:
+        raise ValueError('Unary consumer already consumed!')
+      elif self._terminated:
+        raise ValueError('Unary consumer already terminated!')
+      else:
+        self._consumed = True
+        self._terminated = True
+
+    self._action(value)
+
+
+class _UnaryUnaryAdaptation(object):
+
+  def __init__(self, unary_unary_test_method):
+    self._method = unary_unary_test_method
+
+  def service(self, response_consumer, context, control):
+    def action(request):
+      self._method.service(
+          request, response_consumer.consume_and_terminate, context, control)
+    return _UnaryConsumer(action)
+
+
+class _UnaryStreamAdaptation(object):
+
+  def __init__(self, unary_stream_test_method):
+    self._method = unary_stream_test_method
+
+  def service(self, response_consumer, context, control):
+    def action(request):
+      self._method.service(request, response_consumer, context, control)
+    return _UnaryConsumer(action)
+
+
+class _StreamUnaryAdaptation(object):
+
+  def __init__(self, stream_unary_test_method):
+    self._method = stream_unary_test_method
+
+  def service(self, response_consumer, context, control):
+    return self._method.service(
+        response_consumer.consume_and_terminate, context, control)
+
+
+class _MultiMethodImplementation(face.MultiMethodImplementation):
+
+  def __init__(self, methods, control, pool):
+    self._methods = methods
+    self._control = control
+    self._pool = pool
+
+  def service(self, group, name, response_consumer, context):
+    method = self._methods.get(group, name, None)
+    if method is None:
+      raise face.NoSuchMethodError(group, name)
+    elif self._pool is None:
+      return method(response_consumer, context, self._control)
+    else:
+      request_consumer = method(response_consumer, context, self._control)
+      return stream_util.ThreadSwitchingConsumer(request_consumer, self._pool)
+
+
+class _Assembly(
+    collections.namedtuple(
+        '_Assembly',
+        ['methods', 'inlines', 'events', 'adaptations', 'messages'])):
+  """An intermediate structure created when creating a TestServiceDigest."""
+
+
+def _assemble(
+    scenarios, identifiers, inline_method_constructor, event_method_constructor,
+    adapter, control, pool):
+  """Creates an _Assembly from the given scenarios."""
+  methods = {}
+  inlines = {}
+  events = {}
+  adaptations = {}
+  messages = {}
+  for identifier, scenario in six.iteritems(scenarios):
+    if identifier in identifiers:
+      raise ValueError('Repeated identifier "(%s, %s)"!' % identifier)
+
+    test_method = scenario[0]
+    inline_method = inline_method_constructor(test_method, control)
+    event_method = event_method_constructor(test_method, control, pool)
+    adaptation = adapter(test_method)
+
+    methods[identifier] = test_method
+    inlines[identifier] = inline_method
+    events[identifier] = event_method
+    adaptations[identifier] = adaptation
+    messages[identifier] = scenario[1]
+
+  return _Assembly(methods, inlines, events, adaptations, messages)
+
+
+def digest(service, control, pool):
+  """Creates a TestServiceDigest from a TestService.
+
+  Args:
+    service: A _service.TestService.
+    control: A test_control.Control.
+    pool: If RPC methods should be serviced in a separate thread, a thread pool.
+      None if RPC methods should be serviced in the thread belonging to the
+      run-time that calls for their service.
+
+  Returns:
+    A TestServiceDigest synthesized from the given service.TestService.
+  """
+  identifiers = set()
+
+  unary_unary = _assemble(
+      service.unary_unary_scenarios(), identifiers, _InlineUnaryUnaryMethod,
+      _EventUnaryUnaryMethod, _UnaryUnaryAdaptation, control, pool)
+  identifiers.update(unary_unary.inlines)
+
+  unary_stream = _assemble(
+      service.unary_stream_scenarios(), identifiers, _InlineUnaryStreamMethod,
+      _EventUnaryStreamMethod, _UnaryStreamAdaptation, control, pool)
+  identifiers.update(unary_stream.inlines)
+
+  stream_unary = _assemble(
+      service.stream_unary_scenarios(), identifiers, _InlineStreamUnaryMethod,
+      _EventStreamUnaryMethod, _StreamUnaryAdaptation, control, pool)
+  identifiers.update(stream_unary.inlines)
+
+  stream_stream = _assemble(
+      service.stream_stream_scenarios(), identifiers, _InlineStreamStreamMethod,
+      _EventStreamStreamMethod, _IDENTITY, control, pool)
+  identifiers.update(stream_stream.inlines)
+
+  methods = dict(unary_unary.methods)
+  methods.update(unary_stream.methods)
+  methods.update(stream_unary.methods)
+  methods.update(stream_stream.methods)
+  adaptations = dict(unary_unary.adaptations)
+  adaptations.update(unary_stream.adaptations)
+  adaptations.update(stream_unary.adaptations)
+  adaptations.update(stream_stream.adaptations)
+  inlines = dict(unary_unary.inlines)
+  inlines.update(unary_stream.inlines)
+  inlines.update(stream_unary.inlines)
+  inlines.update(stream_stream.inlines)
+  events = dict(unary_unary.events)
+  events.update(unary_stream.events)
+  events.update(stream_unary.events)
+  events.update(stream_stream.events)
+
+  return TestServiceDigest(
+      methods,
+      inlines,
+      events,
+      _MultiMethodImplementation(adaptations, control, pool),
+      unary_unary.messages,
+      unary_stream.messages,
+      stream_unary.messages,
+      stream_stream.messages)
diff --git a/src/python/grpcio_tests/tests/unit/framework/interfaces/face/_future_invocation_asynchronous_event_service.py b/src/python/grpcio_tests/tests/unit/framework/interfaces/face/_future_invocation_asynchronous_event_service.py
new file mode 100644
index 0000000000..791620307b
--- /dev/null
+++ b/src/python/grpcio_tests/tests/unit/framework/interfaces/face/_future_invocation_asynchronous_event_service.py
@@ -0,0 +1,480 @@
+# 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.
+
+"""Test code for the Face layer of RPC Framework."""
+
+from __future__ import division
+
+import abc
+import contextlib
+import itertools
+import threading
+import unittest
+from concurrent import futures
+
+import six
+
+# test_interfaces is referenced from specification in this module.
+from grpc.framework.foundation import logging_pool
+from grpc.framework.interfaces.face import face
+from tests.unit.framework.common import test_constants
+from tests.unit.framework.common import test_control
+from tests.unit.framework.common import test_coverage
+from tests.unit.framework.interfaces.face import _3069_test_constant
+from tests.unit.framework.interfaces.face import _digest
+from tests.unit.framework.interfaces.face import _stock_service
+from tests.unit.framework.interfaces.face import test_interfaces  # pylint: disable=unused-import
+
+
+class _PauseableIterator(object):
+
+  def __init__(self, upstream):
+    self._upstream = upstream
+    self._condition = threading.Condition()
+    self._paused = False
+
+  @contextlib.contextmanager
+  def pause(self):
+    with self._condition:
+      self._paused = True
+    yield
+    with self._condition:
+      self._paused = False
+      self._condition.notify_all()
+
+  def __iter__(self):
+    return self
+
+  def __next__(self):
+    return self.next()
+
+  def next(self):
+    with self._condition:
+      while self._paused:
+        self._condition.wait()
+    return next(self._upstream)
+
+
+class _Callback(object):
+
+  def __init__(self):
+    self._condition = threading.Condition()
+    self._called = False
+    self._passed_future = None
+    self._passed_other_stuff = None
+
+  def __call__(self, *args, **kwargs):
+    with self._condition:
+      self._called = True
+      if args:
+        self._passed_future = args[0]
+      if 1 < len(args) or kwargs:
+        self._passed_other_stuff = tuple(args[1:]), dict(kwargs)
+      self._condition.notify_all()
+
+  def future(self):
+    with self._condition:
+      while True:
+        if self._passed_other_stuff is not None:
+          raise ValueError(
+              'Test callback passed unexpected values: %s',
+              self._passed_other_stuff)
+        elif self._called:
+          return self._passed_future
+        else:
+          self._condition.wait()
+
+
+class TestCase(six.with_metaclass(abc.ABCMeta, test_coverage.Coverage, unittest.TestCase)):
+  """A test of the Face layer of RPC Framework.
+
+  Concrete subclasses must have an "implementation" attribute of type
+  test_interfaces.Implementation and an "invoker_constructor" attribute of type
+  _invocation.InvokerConstructor.
+  """
+
+  NAME = 'FutureInvocationAsynchronousEventServiceTest'
+
+  def setUp(self):
+    """See unittest.TestCase.setUp for full specification.
+
+    Overriding implementations must call this implementation.
+    """
+    self._control = test_control.PauseFailControl()
+    self._digest_pool = logging_pool.pool(test_constants.POOL_SIZE)
+    self._digest = _digest.digest(
+        _stock_service.STOCK_TEST_SERVICE, self._control, self._digest_pool)
+
+    generic_stub, dynamic_stubs, self._memo = self.implementation.instantiate(
+        self._digest.methods, self._digest.event_method_implementations, None)
+    self._invoker = self.invoker_constructor.construct_invoker(
+        generic_stub, dynamic_stubs, self._digest.methods)
+
+  def tearDown(self):
+    """See unittest.TestCase.tearDown for full specification.
+
+    Overriding implementations must call this implementation.
+    """
+    self._invoker = None
+    self.implementation.destantiate(self._memo)
+    self._digest_pool.shutdown(wait=True)
+
+  def testSuccessfulUnaryRequestUnaryResponse(self):
+    for (group, method), test_messages_sequence in (
+        six.iteritems(self._digest.unary_unary_messages_sequences)):
+      for test_messages in test_messages_sequence:
+        request = test_messages.request()
+        callback = _Callback()
+
+        response_future = self._invoker.future(group, method)(
+            request, test_constants.LONG_TIMEOUT)
+        response_future.add_done_callback(callback)
+        response = response_future.result()
+
+        test_messages.verify(request, response, self)
+        self.assertIs(callback.future(), response_future)
+
+  def testSuccessfulUnaryRequestStreamResponse(self):
+    for (group, method), test_messages_sequence in (
+        six.iteritems(self._digest.unary_stream_messages_sequences)):
+      for test_messages in test_messages_sequence:
+        request = test_messages.request()
+
+        response_iterator = self._invoker.future(group, method)(
+            request, test_constants.LONG_TIMEOUT)
+        responses = list(response_iterator)
+
+        test_messages.verify(request, responses, self)
+
+  def testSuccessfulStreamRequestUnaryResponse(self):
+    for (group, method), test_messages_sequence in (
+        six.iteritems(self._digest.stream_unary_messages_sequences)):
+      for test_messages in test_messages_sequence:
+        requests = test_messages.requests()
+        request_iterator = _PauseableIterator(iter(requests))
+        callback = _Callback()
+
+        # Use of a paused iterator of requests allows us to test that control is
+        # returned to calling code before the iterator yields any requests.
+        with request_iterator.pause():
+          response_future = self._invoker.future(group, method)(
+              request_iterator, test_constants.LONG_TIMEOUT)
+          response_future.add_done_callback(callback)
+        future_passed_to_callback = callback.future()
+        response = future_passed_to_callback.result()
+
+        test_messages.verify(requests, response, self)
+        self.assertIs(future_passed_to_callback, response_future)
+
+  def testSuccessfulStreamRequestStreamResponse(self):
+    for (group, method), test_messages_sequence in (
+        six.iteritems(self._digest.stream_stream_messages_sequences)):
+      for test_messages in test_messages_sequence:
+        requests = test_messages.requests()
+        request_iterator = _PauseableIterator(iter(requests))
+
+        # Use of a paused iterator of requests allows us to test that control is
+        # returned to calling code before the iterator yields any requests.
+        with request_iterator.pause():
+          response_iterator = self._invoker.future(group, method)(
+              request_iterator, test_constants.LONG_TIMEOUT)
+        responses = list(response_iterator)
+
+        test_messages.verify(requests, responses, self)
+
+  def testSequentialInvocations(self):
+    for (group, method), test_messages_sequence in (
+        six.iteritems(self._digest.unary_unary_messages_sequences)):
+      for test_messages in test_messages_sequence:
+        first_request = test_messages.request()
+        second_request = test_messages.request()
+
+        first_response_future = self._invoker.future(group, method)(
+            first_request, test_constants.LONG_TIMEOUT)
+        first_response = first_response_future.result()
+
+        test_messages.verify(first_request, first_response, self)
+
+        second_response_future = self._invoker.future(group, method)(
+            second_request, test_constants.LONG_TIMEOUT)
+        second_response = second_response_future.result()
+
+        test_messages.verify(second_request, second_response, self)
+
+  def testParallelInvocations(self):
+    for (group, method), test_messages_sequence in (
+        six.iteritems(self._digest.unary_unary_messages_sequences)):
+      for test_messages in test_messages_sequence:
+        first_request = test_messages.request()
+        second_request = test_messages.request()
+
+        first_response_future = self._invoker.future(group, method)(
+            first_request, test_constants.LONG_TIMEOUT)
+        second_response_future = self._invoker.future(group, method)(
+            second_request, test_constants.LONG_TIMEOUT)
+        first_response = first_response_future.result()
+        second_response = second_response_future.result()
+
+        test_messages.verify(first_request, first_response, self)
+        test_messages.verify(second_request, second_response, self)
+
+    for (group, method), test_messages_sequence in (
+        six.iteritems(self._digest.unary_unary_messages_sequences)):
+      for test_messages in test_messages_sequence:
+        requests = []
+        response_futures = []
+        for _ in range(test_constants.THREAD_CONCURRENCY):
+          request = test_messages.request()
+          response_future = self._invoker.future(group, method)(
+              request, test_constants.LONG_TIMEOUT)
+          requests.append(request)
+          response_futures.append(response_future)
+
+        responses = [
+            response_future.result() for response_future in response_futures]
+
+        for request, response in zip(requests, responses):
+          test_messages.verify(request, response, self)
+
+  def testWaitingForSomeButNotAllParallelInvocations(self):
+    pool = logging_pool.pool(test_constants.THREAD_CONCURRENCY)
+    for (group, method), test_messages_sequence in (
+        six.iteritems(self._digest.unary_unary_messages_sequences)):
+      for test_messages in test_messages_sequence:
+        requests = []
+        response_futures_to_indices = {}
+        for index in range(test_constants.THREAD_CONCURRENCY):
+          request = test_messages.request()
+          inner_response_future = self._invoker.future(group, method)(
+              request, test_constants.LONG_TIMEOUT)
+          outer_response_future = pool.submit(inner_response_future.result)
+          requests.append(request)
+          response_futures_to_indices[outer_response_future] = index
+
+        some_completed_response_futures_iterator = itertools.islice(
+            futures.as_completed(response_futures_to_indices),
+            test_constants.THREAD_CONCURRENCY // 2)
+        for response_future in some_completed_response_futures_iterator:
+          index = response_futures_to_indices[response_future]
+          test_messages.verify(requests[index], response_future.result(), self)
+    pool.shutdown(wait=True)
+
+  def testCancelledUnaryRequestUnaryResponse(self):
+    for (group, method), test_messages_sequence in (
+        six.iteritems(self._digest.unary_unary_messages_sequences)):
+      for test_messages in test_messages_sequence:
+        request = test_messages.request()
+        callback = _Callback()
+
+        with self._control.pause():
+          response_future = self._invoker.future(group, method)(
+              request, test_constants.LONG_TIMEOUT)
+          response_future.add_done_callback(callback)
+          cancel_method_return_value = response_future.cancel()
+
+        self.assertIs(callback.future(), response_future)
+        self.assertFalse(cancel_method_return_value)
+        self.assertTrue(response_future.cancelled())
+
+  def testCancelledUnaryRequestStreamResponse(self):
+    for (group, method), test_messages_sequence in (
+        six.iteritems(self._digest.unary_stream_messages_sequences)):
+      for test_messages in test_messages_sequence:
+        request = test_messages.request()
+
+        with self._control.pause():
+          response_iterator = self._invoker.future(group, method)(
+              request, test_constants.LONG_TIMEOUT)
+          response_iterator.cancel()
+
+        with self.assertRaises(face.CancellationError):
+          next(response_iterator)
+
+  def testCancelledStreamRequestUnaryResponse(self):
+    for (group, method), test_messages_sequence in (
+        six.iteritems(self._digest.stream_unary_messages_sequences)):
+      for test_messages in test_messages_sequence:
+        requests = test_messages.requests()
+        callback = _Callback()
+
+        with self._control.pause():
+          response_future = self._invoker.future(group, method)(
+              iter(requests), test_constants.LONG_TIMEOUT)
+          response_future.add_done_callback(callback)
+          cancel_method_return_value = response_future.cancel()
+
+        self.assertIs(callback.future(), response_future)
+        self.assertFalse(cancel_method_return_value)
+        self.assertTrue(response_future.cancelled())
+
+  def testCancelledStreamRequestStreamResponse(self):
+    for (group, method), test_messages_sequence in (
+        six.iteritems(self._digest.stream_stream_messages_sequences)):
+      for test_messages in test_messages_sequence:
+        requests = test_messages.requests()
+
+        with self._control.pause():
+          response_iterator = self._invoker.future(group, method)(
+              iter(requests), test_constants.LONG_TIMEOUT)
+          response_iterator.cancel()
+
+        with self.assertRaises(face.CancellationError):
+          next(response_iterator)
+
+  def testExpiredUnaryRequestUnaryResponse(self):
+    for (group, method), test_messages_sequence in (
+        six.iteritems(self._digest.unary_unary_messages_sequences)):
+      for test_messages in test_messages_sequence:
+        request = test_messages.request()
+        callback = _Callback()
+
+        with self._control.pause():
+          response_future = self._invoker.future(
+              group, method)(request, _3069_test_constant.REALLY_SHORT_TIMEOUT)
+          response_future.add_done_callback(callback)
+          self.assertIs(callback.future(), response_future)
+          self.assertIsInstance(
+              response_future.exception(), face.ExpirationError)
+          with self.assertRaises(face.ExpirationError):
+            response_future.result()
+
+  def testExpiredUnaryRequestStreamResponse(self):
+    for (group, method), test_messages_sequence in (
+        six.iteritems(self._digest.unary_stream_messages_sequences)):
+      for test_messages in test_messages_sequence:
+        request = test_messages.request()
+
+        with self._control.pause():
+          response_iterator = self._invoker.future(group, method)(
+              request, _3069_test_constant.REALLY_SHORT_TIMEOUT)
+          with self.assertRaises(face.ExpirationError):
+            list(response_iterator)
+
+  def testExpiredStreamRequestUnaryResponse(self):
+    for (group, method), test_messages_sequence in (
+        six.iteritems(self._digest.stream_unary_messages_sequences)):
+      for test_messages in test_messages_sequence:
+        requests = test_messages.requests()
+        callback = _Callback()
+
+        with self._control.pause():
+          response_future = self._invoker.future(group, method)(
+              iter(requests), _3069_test_constant.REALLY_SHORT_TIMEOUT)
+          response_future.add_done_callback(callback)
+          self.assertIs(callback.future(), response_future)
+          self.assertIsInstance(
+              response_future.exception(), face.ExpirationError)
+          with self.assertRaises(face.ExpirationError):
+            response_future.result()
+
+  def testExpiredStreamRequestStreamResponse(self):
+    for (group, method), test_messages_sequence in (
+        six.iteritems(self._digest.stream_stream_messages_sequences)):
+      for test_messages in test_messages_sequence:
+        requests = test_messages.requests()
+
+        with self._control.pause():
+          response_iterator = self._invoker.future(group, method)(
+              iter(requests), _3069_test_constant.REALLY_SHORT_TIMEOUT)
+          with self.assertRaises(face.ExpirationError):
+            list(response_iterator)
+
+  def testFailedUnaryRequestUnaryResponse(self):
+    for (group, method), test_messages_sequence in (
+        six.iteritems(self._digest.unary_unary_messages_sequences)):
+      for test_messages in test_messages_sequence:
+        request = test_messages.request()
+        callback = _Callback()
+
+        with self._control.fail():
+          response_future = self._invoker.future(group, method)(
+              request, _3069_test_constant.REALLY_SHORT_TIMEOUT)
+          response_future.add_done_callback(callback)
+
+          self.assertIs(callback.future(), response_future)
+          # Because the servicer fails outside of the thread from which the
+          # servicer-side runtime called into it its failure is
+          # indistinguishable from simply not having called its
+          # response_callback before the expiration of the RPC.
+          self.assertIsInstance(
+              response_future.exception(), face.ExpirationError)
+          with self.assertRaises(face.ExpirationError):
+            response_future.result()
+
+  def testFailedUnaryRequestStreamResponse(self):
+    for (group, method), test_messages_sequence in (
+        six.iteritems(self._digest.unary_stream_messages_sequences)):
+      for test_messages in test_messages_sequence:
+        request = test_messages.request()
+
+        # Because the servicer fails outside of the thread from which the
+        # servicer-side runtime called into it its failure is indistinguishable
+        # from simply not having called its response_consumer before the
+        # expiration of the RPC.
+        with self._control.fail(), self.assertRaises(face.ExpirationError):
+          response_iterator = self._invoker.future(group, method)(
+              request, _3069_test_constant.REALLY_SHORT_TIMEOUT)
+          list(response_iterator)
+
+  def testFailedStreamRequestUnaryResponse(self):
+    for (group, method), test_messages_sequence in (
+        six.iteritems(self._digest.stream_unary_messages_sequences)):
+      for test_messages in test_messages_sequence:
+        requests = test_messages.requests()
+        callback = _Callback()
+
+        with self._control.fail():
+          response_future = self._invoker.future(group, method)(
+              iter(requests), _3069_test_constant.REALLY_SHORT_TIMEOUT)
+          response_future.add_done_callback(callback)
+
+          self.assertIs(callback.future(), response_future)
+          # Because the servicer fails outside of the thread from which the
+          # servicer-side runtime called into it its failure is
+          # indistinguishable from simply not having called its
+          # response_callback before the expiration of the RPC.
+          self.assertIsInstance(
+              response_future.exception(), face.ExpirationError)
+          with self.assertRaises(face.ExpirationError):
+            response_future.result()
+
+  def testFailedStreamRequestStreamResponse(self):
+    for (group, method), test_messages_sequence in (
+        six.iteritems(self._digest.stream_stream_messages_sequences)):
+      for test_messages in test_messages_sequence:
+        requests = test_messages.requests()
+
+        # Because the servicer fails outside of the thread from which the
+        # servicer-side runtime called into it its failure is indistinguishable
+        # from simply not having called its response_consumer before the
+        # expiration of the RPC.
+        with self._control.fail(), self.assertRaises(face.ExpirationError):
+          response_iterator = self._invoker.future(group, method)(
+              iter(requests), _3069_test_constant.REALLY_SHORT_TIMEOUT)
+          list(response_iterator)
diff --git a/src/python/grpcio_tests/tests/unit/framework/interfaces/face/_invocation.py b/src/python/grpcio_tests/tests/unit/framework/interfaces/face/_invocation.py
new file mode 100644
index 0000000000..ac487bed4f
--- /dev/null
+++ b/src/python/grpcio_tests/tests/unit/framework/interfaces/face/_invocation.py
@@ -0,0 +1,213 @@
+# 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.
+
+"""Coverage across the Face layer's generic-to-dynamic range for invocation."""
+
+import abc
+
+import six
+
+from grpc.framework.common import cardinality
+
+_CARDINALITY_TO_GENERIC_BLOCKING_BEHAVIOR = {
+    cardinality.Cardinality.UNARY_UNARY: 'blocking_unary_unary',
+    cardinality.Cardinality.UNARY_STREAM: 'inline_unary_stream',
+    cardinality.Cardinality.STREAM_UNARY: 'blocking_stream_unary',
+    cardinality.Cardinality.STREAM_STREAM: 'inline_stream_stream',
+}
+
+_CARDINALITY_TO_GENERIC_FUTURE_BEHAVIOR = {
+    cardinality.Cardinality.UNARY_UNARY: 'future_unary_unary',
+    cardinality.Cardinality.UNARY_STREAM: 'inline_unary_stream',
+    cardinality.Cardinality.STREAM_UNARY: 'future_stream_unary',
+    cardinality.Cardinality.STREAM_STREAM: 'inline_stream_stream',
+}
+
+_CARDINALITY_TO_GENERIC_EVENT_BEHAVIOR = {
+    cardinality.Cardinality.UNARY_UNARY: 'event_unary_unary',
+    cardinality.Cardinality.UNARY_STREAM: 'event_unary_stream',
+    cardinality.Cardinality.STREAM_UNARY: 'event_stream_unary',
+    cardinality.Cardinality.STREAM_STREAM: 'event_stream_stream',
+}
+
+_CARDINALITY_TO_MULTI_CALLABLE_ATTRIBUTE = {
+    cardinality.Cardinality.UNARY_UNARY: 'unary_unary',
+    cardinality.Cardinality.UNARY_STREAM: 'unary_stream',
+    cardinality.Cardinality.STREAM_UNARY: 'stream_unary',
+    cardinality.Cardinality.STREAM_STREAM: 'stream_stream',
+}
+
+
+class Invoker(six.with_metaclass(abc.ABCMeta)):
+  """A type used to invoke test RPCs."""
+
+  @abc.abstractmethod
+  def blocking(self, group, name):
+    """Invokes an RPC with blocking control flow."""
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def future(self, group, name):
+    """Invokes an RPC with future control flow."""
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def event(self, group, name):
+    """Invokes an RPC with event control flow."""
+    raise NotImplementedError()
+
+
+class InvokerConstructor(six.with_metaclass(abc.ABCMeta)):
+  """A type used to create Invokers."""
+
+  @abc.abstractmethod
+  def name(self):
+    """Specifies the name of the Invoker constructed by this object."""
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def construct_invoker(self, generic_stub, dynamic_stubs, methods):
+    """Constructs an Invoker for the given stubs and methods."""
+    raise NotImplementedError()
+
+
+class _GenericInvoker(Invoker):
+
+  def __init__(self, generic_stub, methods):
+    self._stub = generic_stub
+    self._methods = methods
+
+  def _behavior(self, group, name, cardinality_to_generic_method):
+    method_cardinality = self._methods[group, name].cardinality()
+    behavior = getattr(
+        self._stub, cardinality_to_generic_method[method_cardinality])
+    return lambda *args, **kwargs: behavior(group, name, *args, **kwargs)
+
+  def blocking(self, group, name):
+    return self._behavior(
+        group, name, _CARDINALITY_TO_GENERIC_BLOCKING_BEHAVIOR)
+
+  def future(self, group, name):
+    return self._behavior(group, name, _CARDINALITY_TO_GENERIC_FUTURE_BEHAVIOR)
+
+  def event(self, group, name):
+    return self._behavior(group, name, _CARDINALITY_TO_GENERIC_EVENT_BEHAVIOR)
+
+
+class _GenericInvokerConstructor(InvokerConstructor):
+
+  def name(self):
+    return 'GenericInvoker'
+
+  def construct_invoker(self, generic_stub, dynamic_stub, methods):
+    return _GenericInvoker(generic_stub, methods)
+
+
+class _MultiCallableInvoker(Invoker):
+
+  def __init__(self, generic_stub, methods):
+    self._stub = generic_stub
+    self._methods = methods
+
+  def _multi_callable(self, group, name):
+    method_cardinality = self._methods[group, name].cardinality()
+    behavior = getattr(
+        self._stub,
+        _CARDINALITY_TO_MULTI_CALLABLE_ATTRIBUTE[method_cardinality])
+    return behavior(group, name)
+
+  def blocking(self, group, name):
+    return self._multi_callable(group, name)
+
+  def future(self, group, name):
+    method_cardinality = self._methods[group, name].cardinality()
+    behavior = getattr(
+        self._stub,
+        _CARDINALITY_TO_MULTI_CALLABLE_ATTRIBUTE[method_cardinality])
+    if method_cardinality in (
+        cardinality.Cardinality.UNARY_UNARY,
+        cardinality.Cardinality.STREAM_UNARY):
+      return behavior(group, name).future
+    else:
+      return behavior(group, name)
+
+  def event(self, group, name):
+    return self._multi_callable(group, name).event
+
+
+class _MultiCallableInvokerConstructor(InvokerConstructor):
+
+  def name(self):
+    return 'MultiCallableInvoker'
+
+  def construct_invoker(self, generic_stub, dynamic_stub, methods):
+    return _MultiCallableInvoker(generic_stub, methods)
+
+
+class _DynamicInvoker(Invoker):
+
+  def __init__(self, dynamic_stubs, methods):
+    self._stubs = dynamic_stubs
+    self._methods = methods
+
+  def blocking(self, group, name):
+    return getattr(self._stubs[group], name)
+
+  def future(self, group, name):
+    if self._methods[group, name].cardinality() in (
+        cardinality.Cardinality.UNARY_UNARY,
+        cardinality.Cardinality.STREAM_UNARY):
+      return getattr(self._stubs[group], name).future
+    else:
+      return getattr(self._stubs[group], name)
+
+  def event(self, group, name):
+    return getattr(self._stubs[group], name).event
+
+
+class _DynamicInvokerConstructor(InvokerConstructor):
+
+  def name(self):
+    return 'DynamicInvoker'
+
+  def construct_invoker(self, generic_stub, dynamic_stubs, methods):
+    return _DynamicInvoker(dynamic_stubs, methods)
+
+
+def invoker_constructors():
+  """Creates a sequence of InvokerConstructors to use in tests of RPCs.
+
+  Returns:
+    A sequence of InvokerConstructors.
+  """
+  return (
+      _GenericInvokerConstructor(),
+      _MultiCallableInvokerConstructor(),
+      _DynamicInvokerConstructor(),
+  )
diff --git a/src/python/grpcio_tests/tests/unit/framework/interfaces/face/_receiver.py b/src/python/grpcio_tests/tests/unit/framework/interfaces/face/_receiver.py
new file mode 100644
index 0000000000..48f31fc677
--- /dev/null
+++ b/src/python/grpcio_tests/tests/unit/framework/interfaces/face/_receiver.py
@@ -0,0 +1,95 @@
+# 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.
+
+"""A utility useful in tests of asynchronous, event-driven interfaces."""
+
+import threading
+
+from grpc.framework.interfaces.face import face
+
+
+class Receiver(face.ResponseReceiver):
+  """A utility object useful in tests of asynchronous code."""
+
+  def __init__(self):
+    self._condition = threading.Condition()
+    self._initial_metadata = None
+    self._responses = []
+    self._terminal_metadata = None
+    self._code = None
+    self._details = None
+    self._completed = False
+    self._abortion = None
+
+  def abort(self, abortion):
+    with self._condition:
+      self._abortion = abortion
+      self._condition.notify_all()
+
+  def initial_metadata(self, initial_metadata):
+    with self._condition:
+      self._initial_metadata = initial_metadata
+
+  def response(self, response):
+    with self._condition:
+      self._responses.append(response)
+
+  def complete(self, terminal_metadata, code, details):
+    with self._condition:
+      self._terminal_metadata = terminal_metadata
+      self._code = code
+      self._details = details
+      self._completed = True
+      self._condition.notify_all()
+
+  def block_until_terminated(self):
+    with self._condition:
+      while self._abortion is None and not self._completed:
+        self._condition.wait()
+
+  def unary_response(self):
+    with self._condition:
+      if self._abortion is not None:
+        raise AssertionError('Aborted: "{}"!'.format(self._abortion))
+      elif len(self._responses) != 1:
+        raise AssertionError(
+            '%d responses received, not exactly one!', len(self._responses))
+      else:
+        return self._responses[0]
+
+  def stream_responses(self):
+    with self._condition:
+      if self._abortion is None:
+        return list(self._responses)
+      else:
+        raise AssertionError('Aborted: "{}"!'.format(self._abortion))
+
+  def abortion(self):
+    with self._condition:
+      return self._abortion
diff --git a/src/python/grpcio_tests/tests/unit/framework/interfaces/face/_service.py b/src/python/grpcio_tests/tests/unit/framework/interfaces/face/_service.py
new file mode 100644
index 0000000000..f13dff0558
--- /dev/null
+++ b/src/python/grpcio_tests/tests/unit/framework/interfaces/face/_service.py
@@ -0,0 +1,316 @@
+# 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.
+
+"""Private interfaces implemented by data sets used in Face-layer tests."""
+
+import abc
+
+import six
+
+# face is referenced from specification in this module.
+from grpc.framework.interfaces.face import face  # pylint: disable=unused-import
+from tests.unit.framework.interfaces.face import test_interfaces
+
+
+class UnaryUnaryTestMethodImplementation(six.with_metaclass(abc.ABCMeta, test_interfaces.Method)):
+  """A controllable implementation of a unary-unary method."""
+
+  @abc.abstractmethod
+  def service(self, request, response_callback, context, control):
+    """Services an RPC that accepts one message and produces one message.
+
+    Args:
+      request: The single request message for the RPC.
+      response_callback: A callback to be called to accept the response message
+        of the RPC.
+      context: An face.ServicerContext object.
+      control: A test_control.Control to control execution of this method.
+
+    Raises:
+      abandonment.Abandoned: May or may not be raised when the RPC has been
+        aborted.
+    """
+    raise NotImplementedError()
+
+
+class UnaryUnaryTestMessages(six.with_metaclass(abc.ABCMeta)):
+  """A type for unary-request-unary-response message pairings."""
+
+  @abc.abstractmethod
+  def request(self):
+    """Affords a request message.
+
+    Implementations of this method should return a different message with each
+    call so that multiple test executions of the test method may be made with
+    different inputs.
+
+    Returns:
+      A request message.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def verify(self, request, response, test_case):
+    """Verifies that the computed response matches the given request.
+
+    Args:
+      request: A request message.
+      response: A response message.
+      test_case: A unittest.TestCase object affording useful assertion methods.
+
+    Raises:
+      AssertionError: If the request and response do not match, indicating that
+        there was some problem executing the RPC under test.
+    """
+    raise NotImplementedError()
+
+
+class UnaryStreamTestMethodImplementation(six.with_metaclass(abc.ABCMeta, test_interfaces.Method)):
+  """A controllable implementation of a unary-stream method."""
+
+  @abc.abstractmethod
+  def service(self, request, response_consumer, context, control):
+    """Services an RPC that takes one message and produces a stream of messages.
+
+    Args:
+      request: The single request message for the RPC.
+      response_consumer: A stream.Consumer to be called to accept the response
+        messages of the RPC.
+      context: A face.ServicerContext object.
+      control: A test_control.Control to control execution of this method.
+
+    Raises:
+      abandonment.Abandoned: May or may not be raised when the RPC has been
+        aborted.
+    """
+    raise NotImplementedError()
+
+
+class UnaryStreamTestMessages(six.with_metaclass(abc.ABCMeta)):
+  """A type for unary-request-stream-response message pairings."""
+
+  @abc.abstractmethod
+  def request(self):
+    """Affords a request message.
+
+    Implementations of this method should return a different message with each
+    call so that multiple test executions of the test method may be made with
+    different inputs.
+
+    Returns:
+      A request message.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def verify(self, request, responses, test_case):
+    """Verifies that the computed responses match the given request.
+
+    Args:
+      request: A request message.
+      responses: A sequence of response messages.
+      test_case: A unittest.TestCase object affording useful assertion methods.
+
+    Raises:
+      AssertionError: If the request and responses do not match, indicating that
+        there was some problem executing the RPC under test.
+    """
+    raise NotImplementedError()
+
+
+class StreamUnaryTestMethodImplementation(six.with_metaclass(abc.ABCMeta, test_interfaces.Method)):
+  """A controllable implementation of a stream-unary method."""
+
+  @abc.abstractmethod
+  def service(self, response_callback, context, control):
+    """Services an RPC that takes a stream of messages and produces one message.
+
+    Args:
+      response_callback: A callback to be called to accept the response message
+        of the RPC.
+      context: A face.ServicerContext object.
+      control: A test_control.Control to control execution of this method.
+
+    Returns:
+      A stream.Consumer with which to accept the request messages of the RPC.
+        The consumer returned from this method may or may not be invoked to
+        completion: in the case of RPC abortion, RPC Framework will simply stop
+        passing messages to this object. Implementations must not assume that
+        this object will be called to completion of the request stream or even
+        called at all.
+
+    Raises:
+      abandonment.Abandoned: May or may not be raised when the RPC has been
+        aborted.
+    """
+    raise NotImplementedError()
+
+
+class StreamUnaryTestMessages(six.with_metaclass(abc.ABCMeta)):
+  """A type for stream-request-unary-response message pairings."""
+
+  @abc.abstractmethod
+  def requests(self):
+    """Affords a sequence of request messages.
+
+    Implementations of this method should return a different sequences with each
+    call so that multiple test executions of the test method may be made with
+    different inputs.
+
+    Returns:
+      A sequence of request messages.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def verify(self, requests, response, test_case):
+    """Verifies that the computed response matches the given requests.
+
+    Args:
+      requests: A sequence of request messages.
+      response: A response message.
+      test_case: A unittest.TestCase object affording useful assertion methods.
+
+    Raises:
+      AssertionError: If the requests and response do not match, indicating that
+        there was some problem executing the RPC under test.
+    """
+    raise NotImplementedError()
+
+
+class StreamStreamTestMethodImplementation(six.with_metaclass(abc.ABCMeta, test_interfaces.Method)):
+  """A controllable implementation of a stream-stream method."""
+
+  @abc.abstractmethod
+  def service(self, response_consumer, context, control):
+    """Services an RPC that accepts and produces streams of messages.
+
+    Args:
+      response_consumer: A stream.Consumer to be called to accept the response
+        messages of the RPC.
+      context: A face.ServicerContext object.
+      control: A test_control.Control to control execution of this method.
+
+    Returns:
+      A stream.Consumer with which to accept the request messages of the RPC.
+        The consumer returned from this method may or may not be invoked to
+        completion: in the case of RPC abortion, RPC Framework will simply stop
+        passing messages to this object. Implementations must not assume that
+        this object will be called to completion of the request stream or even
+        called at all.
+
+    Raises:
+      abandonment.Abandoned: May or may not be raised when the RPC has been
+        aborted.
+    """
+    raise NotImplementedError()
+
+
+class StreamStreamTestMessages(six.with_metaclass(abc.ABCMeta)):
+  """A type for stream-request-stream-response message pairings."""
+
+  @abc.abstractmethod
+  def requests(self):
+    """Affords a sequence of request messages.
+
+    Implementations of this method should return a different sequences with each
+    call so that multiple test executions of the test method may be made with
+    different inputs.
+
+    Returns:
+      A sequence of request messages.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def verify(self, requests, responses, test_case):
+    """Verifies that the computed response matches the given requests.
+
+    Args:
+      requests: A sequence of request messages.
+      responses: A sequence of response messages.
+      test_case: A unittest.TestCase object affording useful assertion methods.
+
+    Raises:
+      AssertionError: If the requests and responses do not match, indicating
+        that there was some problem executing the RPC under test.
+    """
+    raise NotImplementedError()
+
+
+class TestService(six.with_metaclass(abc.ABCMeta)):
+  """A specification of implemented methods to use in tests."""
+
+  @abc.abstractmethod
+  def unary_unary_scenarios(self):
+    """Affords unary-request-unary-response test methods and their messages.
+
+    Returns:
+      A dict from method group-name pair to implementation/messages pair. The
+        first element of the pair is a UnaryUnaryTestMethodImplementation object
+        and the second element is a sequence of UnaryUnaryTestMethodMessages
+        objects.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def unary_stream_scenarios(self):
+    """Affords unary-request-stream-response test methods and their messages.
+
+    Returns:
+      A dict from method group-name pair to implementation/messages pair. The
+        first element of the pair is a UnaryStreamTestMethodImplementation
+        object and the second element is a sequence of
+        UnaryStreamTestMethodMessages objects.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def stream_unary_scenarios(self):
+    """Affords stream-request-unary-response test methods and their messages.
+
+    Returns:
+      A dict from method group-name pair to implementation/messages pair. The
+        first element of the pair is a StreamUnaryTestMethodImplementation
+        object and the second element is a sequence of
+        StreamUnaryTestMethodMessages objects.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def stream_stream_scenarios(self):
+    """Affords stream-request-stream-response test methods and their messages.
+
+    Returns:
+      A dict from method group-name pair to implementation/messages pair. The
+        first element of the pair is a StreamStreamTestMethodImplementation
+        object and the second element is a sequence of
+        StreamStreamTestMethodMessages objects.
+    """
+    raise NotImplementedError()
diff --git a/src/python/grpcio_tests/tests/unit/framework/interfaces/face/_stock_service.py b/src/python/grpcio_tests/tests/unit/framework/interfaces/face/_stock_service.py
new file mode 100644
index 0000000000..5299655bb3
--- /dev/null
+++ b/src/python/grpcio_tests/tests/unit/framework/interfaces/face/_stock_service.py
@@ -0,0 +1,396 @@
+# 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.
+
+"""Examples of Python implementations of the stock.proto Stock service."""
+
+from grpc.framework.common import cardinality
+from grpc.framework.foundation import abandonment
+from grpc.framework.foundation import stream
+from tests.unit.framework.common import test_constants
+from tests.unit.framework.interfaces.face import _service
+from tests.unit._junkdrawer import stock_pb2
+
+_STOCK_GROUP_NAME = 'Stock'
+_SYMBOL_FORMAT = 'test symbol:%03d'
+
+# A test-appropriate security-pricing function. :-P
+_price = lambda symbol_name: float(hash(symbol_name) % 4096)
+
+
+def _get_last_trade_price(stock_request, stock_reply_callback, control, active):
+  """A unary-request, unary-response test method."""
+  control.control()
+  if active():
+    stock_reply_callback(
+        stock_pb2.StockReply(
+            symbol=stock_request.symbol, price=_price(stock_request.symbol)))
+  else:
+    raise abandonment.Abandoned()
+
+
+def _get_last_trade_price_multiple(stock_reply_consumer, control, active):
+  """A stream-request, stream-response test method."""
+  def stock_reply_for_stock_request(stock_request):
+    control.control()
+    if active():
+      return stock_pb2.StockReply(
+          symbol=stock_request.symbol, price=_price(stock_request.symbol))
+    else:
+      raise abandonment.Abandoned()
+
+  class StockRequestConsumer(stream.Consumer):
+
+    def consume(self, stock_request):
+      stock_reply_consumer.consume(stock_reply_for_stock_request(stock_request))
+
+    def terminate(self):
+      control.control()
+      stock_reply_consumer.terminate()
+
+    def consume_and_terminate(self, stock_request):
+      stock_reply_consumer.consume_and_terminate(
+          stock_reply_for_stock_request(stock_request))
+
+  return StockRequestConsumer()
+
+
+def _watch_future_trades(stock_request, stock_reply_consumer, control, active):
+  """A unary-request, stream-response test method."""
+  base_price = _price(stock_request.symbol)
+  for index in range(stock_request.num_trades_to_watch):
+    control.control()
+    if active():
+      stock_reply_consumer.consume(
+          stock_pb2.StockReply(
+              symbol=stock_request.symbol, price=base_price + index))
+    else:
+      raise abandonment.Abandoned()
+  stock_reply_consumer.terminate()
+
+
+def _get_highest_trade_price(stock_reply_callback, control, active):
+  """A stream-request, unary-response test method."""
+
+  class StockRequestConsumer(stream.Consumer):
+    """Keeps an ongoing record of the most valuable symbol yet consumed."""
+
+    def __init__(self):
+      self._symbol = None
+      self._price = None
+
+    def consume(self, stock_request):
+      control.control()
+      if active():
+        if self._price is None:
+          self._symbol = stock_request.symbol
+          self._price = _price(stock_request.symbol)
+        else:
+          candidate_price = _price(stock_request.symbol)
+          if self._price < candidate_price:
+            self._symbol = stock_request.symbol
+            self._price = candidate_price
+
+    def terminate(self):
+      control.control()
+      if active():
+        if self._symbol is None:
+          raise ValueError()
+        else:
+          stock_reply_callback(
+              stock_pb2.StockReply(symbol=self._symbol, price=self._price))
+          self._symbol = None
+          self._price = None
+
+    def consume_and_terminate(self, stock_request):
+      control.control()
+      if active():
+        if self._price is None:
+          stock_reply_callback(
+              stock_pb2.StockReply(
+                  symbol=stock_request.symbol,
+                  price=_price(stock_request.symbol)))
+        else:
+          candidate_price = _price(stock_request.symbol)
+          if self._price < candidate_price:
+            stock_reply_callback(
+                stock_pb2.StockReply(
+                    symbol=stock_request.symbol, price=candidate_price))
+          else:
+            stock_reply_callback(
+                stock_pb2.StockReply(
+                    symbol=self._symbol, price=self._price))
+
+        self._symbol = None
+        self._price = None
+
+  return StockRequestConsumer()
+
+
+class GetLastTradePrice(_service.UnaryUnaryTestMethodImplementation):
+  """GetLastTradePrice for use in tests."""
+
+  def group(self):
+    return _STOCK_GROUP_NAME
+
+  def name(self):
+    return 'GetLastTradePrice'
+
+  def cardinality(self):
+    return cardinality.Cardinality.UNARY_UNARY
+
+  def request_class(self):
+    return stock_pb2.StockRequest
+
+  def response_class(self):
+    return stock_pb2.StockReply
+
+  def serialize_request(self, request):
+    return request.SerializeToString()
+
+  def deserialize_request(self, serialized_request):
+    return stock_pb2.StockRequest.FromString(serialized_request)
+
+  def serialize_response(self, response):
+    return response.SerializeToString()
+
+  def deserialize_response(self, serialized_response):
+    return stock_pb2.StockReply.FromString(serialized_response)
+
+  def service(self, request, response_callback, context, control):
+    _get_last_trade_price(
+        request, response_callback, control, context.is_active)
+
+
+class GetLastTradePriceMessages(_service.UnaryUnaryTestMessages):
+
+  def __init__(self):
+    self._index = 0
+
+  def request(self):
+    symbol = _SYMBOL_FORMAT % self._index
+    self._index += 1
+    return stock_pb2.StockRequest(symbol=symbol)
+
+  def verify(self, request, response, test_case):
+    test_case.assertEqual(request.symbol, response.symbol)
+    test_case.assertEqual(_price(request.symbol), response.price)
+
+
+class GetLastTradePriceMultiple(_service.StreamStreamTestMethodImplementation):
+  """GetLastTradePriceMultiple for use in tests."""
+
+  def group(self):
+    return _STOCK_GROUP_NAME
+
+  def name(self):
+    return 'GetLastTradePriceMultiple'
+
+  def cardinality(self):
+    return cardinality.Cardinality.STREAM_STREAM
+
+  def request_class(self):
+    return stock_pb2.StockRequest
+
+  def response_class(self):
+    return stock_pb2.StockReply
+
+  def serialize_request(self, request):
+    return request.SerializeToString()
+
+  def deserialize_request(self, serialized_request):
+    return stock_pb2.StockRequest.FromString(serialized_request)
+
+  def serialize_response(self, response):
+    return response.SerializeToString()
+
+  def deserialize_response(self, serialized_response):
+    return stock_pb2.StockReply.FromString(serialized_response)
+
+  def service(self, response_consumer, context, control):
+    return _get_last_trade_price_multiple(
+        response_consumer, control, context.is_active)
+
+
+class GetLastTradePriceMultipleMessages(_service.StreamStreamTestMessages):
+  """Pairs of message streams for use with GetLastTradePriceMultiple."""
+
+  def __init__(self):
+    self._index = 0
+
+  def requests(self):
+    base_index = self._index
+    self._index += 1
+    return [
+        stock_pb2.StockRequest(symbol=_SYMBOL_FORMAT % (base_index + index))
+        for index in range(test_constants.STREAM_LENGTH)]
+
+  def verify(self, requests, responses, test_case):
+    test_case.assertEqual(len(requests), len(responses))
+    for stock_request, stock_reply in zip(requests, responses):
+      test_case.assertEqual(stock_request.symbol, stock_reply.symbol)
+      test_case.assertEqual(_price(stock_request.symbol), stock_reply.price)
+
+
+class WatchFutureTrades(_service.UnaryStreamTestMethodImplementation):
+  """WatchFutureTrades for use in tests."""
+
+  def group(self):
+    return _STOCK_GROUP_NAME
+
+  def name(self):
+    return 'WatchFutureTrades'
+
+  def cardinality(self):
+    return cardinality.Cardinality.UNARY_STREAM
+
+  def request_class(self):
+    return stock_pb2.StockRequest
+
+  def response_class(self):
+    return stock_pb2.StockReply
+
+  def serialize_request(self, request):
+    return request.SerializeToString()
+
+  def deserialize_request(self, serialized_request):
+    return stock_pb2.StockRequest.FromString(serialized_request)
+
+  def serialize_response(self, response):
+    return response.SerializeToString()
+
+  def deserialize_response(self, serialized_response):
+    return stock_pb2.StockReply.FromString(serialized_response)
+
+  def service(self, request, response_consumer, context, control):
+    _watch_future_trades(request, response_consumer, control, context.is_active)
+
+
+class WatchFutureTradesMessages(_service.UnaryStreamTestMessages):
+  """Pairs of a single request message and a sequence of response messages."""
+
+  def __init__(self):
+    self._index = 0
+
+  def request(self):
+    symbol = _SYMBOL_FORMAT % self._index
+    self._index += 1
+    return stock_pb2.StockRequest(
+        symbol=symbol, num_trades_to_watch=test_constants.STREAM_LENGTH)
+
+  def verify(self, request, responses, test_case):
+    test_case.assertEqual(test_constants.STREAM_LENGTH, len(responses))
+    base_price = _price(request.symbol)
+    for index, response in enumerate(responses):
+      test_case.assertEqual(base_price + index, response.price)
+
+
+class GetHighestTradePrice(_service.StreamUnaryTestMethodImplementation):
+  """GetHighestTradePrice for use in tests."""
+
+  def group(self):
+    return _STOCK_GROUP_NAME
+
+  def name(self):
+    return 'GetHighestTradePrice'
+
+  def cardinality(self):
+    return cardinality.Cardinality.STREAM_UNARY
+
+  def request_class(self):
+    return stock_pb2.StockRequest
+
+  def response_class(self):
+    return stock_pb2.StockReply
+
+  def serialize_request(self, request):
+    return request.SerializeToString()
+
+  def deserialize_request(self, serialized_request):
+    return stock_pb2.StockRequest.FromString(serialized_request)
+
+  def serialize_response(self, response):
+    return response.SerializeToString()
+
+  def deserialize_response(self, serialized_response):
+    return stock_pb2.StockReply.FromString(serialized_response)
+
+  def service(self, response_callback, context, control):
+    return _get_highest_trade_price(
+        response_callback, control, context.is_active)
+
+
+class GetHighestTradePriceMessages(_service.StreamUnaryTestMessages):
+
+  def requests(self):
+    return [
+        stock_pb2.StockRequest(symbol=_SYMBOL_FORMAT % index)
+        for index in range(test_constants.STREAM_LENGTH)]
+
+  def verify(self, requests, response, test_case):
+    price = None
+    symbol = None
+    for stock_request in requests:
+      current_symbol = stock_request.symbol
+      current_price = _price(current_symbol)
+      if price is None or price < current_price:
+        price = current_price
+        symbol = current_symbol
+    test_case.assertEqual(price, response.price)
+    test_case.assertEqual(symbol, response.symbol)
+
+
+class StockTestService(_service.TestService):
+  """A corpus of test data with one method of each RPC cardinality."""
+
+  def unary_unary_scenarios(self):
+    return {
+        (_STOCK_GROUP_NAME, 'GetLastTradePrice'): (
+            GetLastTradePrice(), [GetLastTradePriceMessages()]),
+    }
+
+  def unary_stream_scenarios(self):
+    return {
+        (_STOCK_GROUP_NAME, 'WatchFutureTrades'): (
+            WatchFutureTrades(), [WatchFutureTradesMessages()]),
+    }
+
+  def stream_unary_scenarios(self):
+    return {
+        (_STOCK_GROUP_NAME, 'GetHighestTradePrice'): (
+            GetHighestTradePrice(), [GetHighestTradePriceMessages()])
+    }
+
+  def stream_stream_scenarios(self):
+    return {
+        (_STOCK_GROUP_NAME, 'GetLastTradePriceMultiple'): (
+            GetLastTradePriceMultiple(), [GetLastTradePriceMultipleMessages()]),
+    }
+
+
+STOCK_TEST_SERVICE = StockTestService()
diff --git a/src/python/grpcio_tests/tests/unit/framework/interfaces/face/test_cases.py b/src/python/grpcio_tests/tests/unit/framework/interfaces/face/test_cases.py
new file mode 100644
index 0000000000..71de9d835e
--- /dev/null
+++ b/src/python/grpcio_tests/tests/unit/framework/interfaces/face/test_cases.py
@@ -0,0 +1,67 @@
+# 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.
+
+"""Tools for creating tests of implementations of the Face layer."""
+
+# unittest is referenced from specification in this module.
+import unittest  # pylint: disable=unused-import
+
+# test_interfaces is referenced from specification in this module.
+from tests.unit.framework.interfaces.face import _blocking_invocation_inline_service
+from tests.unit.framework.interfaces.face import _future_invocation_asynchronous_event_service
+from tests.unit.framework.interfaces.face import _invocation
+from tests.unit.framework.interfaces.face import test_interfaces  # pylint: disable=unused-import
+
+_TEST_CASE_SUPERCLASSES = (
+    _blocking_invocation_inline_service.TestCase,
+    _future_invocation_asynchronous_event_service.TestCase,
+)
+
+
+def test_cases(implementation):
+  """Creates unittest.TestCase classes for a given Face layer implementation.
+
+  Args:
+    implementation: A test_interfaces.Implementation specifying creation and
+      destruction of a given Face layer implementation.
+
+  Returns:
+    A sequence of subclasses of unittest.TestCase defining tests of the
+      specified Face layer implementation.
+  """
+  test_case_classes = []
+  for invoker_constructor in _invocation.invoker_constructors():
+    for super_class in _TEST_CASE_SUPERCLASSES:
+      test_case_classes.append(
+          type(invoker_constructor.name() + super_class.NAME, (super_class,),
+               {'implementation': implementation,
+                'invoker_constructor': invoker_constructor,
+                '__module__': implementation.__module__,
+               }))
+  return test_case_classes
diff --git a/src/python/grpcio_tests/tests/unit/framework/interfaces/face/test_interfaces.py b/src/python/grpcio_tests/tests/unit/framework/interfaces/face/test_interfaces.py
new file mode 100644
index 0000000000..40f38e68ba
--- /dev/null
+++ b/src/python/grpcio_tests/tests/unit/framework/interfaces/face/test_interfaces.py
@@ -0,0 +1,229 @@
+# 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.
+
+"""Interfaces used in tests of implementations of the Face layer."""
+
+import abc
+
+import six
+
+from grpc.framework.common import cardinality  # pylint: disable=unused-import
+from grpc.framework.interfaces.face import face  # pylint: disable=unused-import
+
+
+class Method(six.with_metaclass(abc.ABCMeta)):
+  """Specifies a method to be used in tests."""
+
+  @abc.abstractmethod
+  def group(self):
+    """Identify the group of the method.
+
+    Returns:
+      The group of the method.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def name(self):
+    """Identify the name of the method.
+
+    Returns:
+      The name of the method.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def cardinality(self):
+    """Identify the cardinality of the method.
+
+    Returns:
+      A cardinality.Cardinality value describing the streaming semantics of the
+        method.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def request_class(self):
+    """Identify the class used for the method's request objects.
+
+    Returns:
+      The class object of the class to which the method's request objects
+        belong.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def response_class(self):
+    """Identify the class used for the method's response objects.
+
+    Returns:
+      The class object of the class to which the method's response objects
+        belong.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def serialize_request(self, request):
+    """Serialize the given request object.
+
+    Args:
+      request: A request object appropriate for this method.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def deserialize_request(self, serialized_request):
+    """Synthesize a request object from a given bytestring.
+
+    Args:
+      serialized_request: A bytestring deserializable into a request object
+        appropriate for this method.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def serialize_response(self, response):
+    """Serialize the given response object.
+
+    Args:
+      response: A response object appropriate for this method.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def deserialize_response(self, serialized_response):
+    """Synthesize a response object from a given bytestring.
+
+    Args:
+      serialized_response: A bytestring deserializable into a response object
+        appropriate for this method.
+    """
+    raise NotImplementedError()
+
+
+class Implementation(six.with_metaclass(abc.ABCMeta)):
+  """Specifies an implementation of the Face layer."""
+
+  @abc.abstractmethod
+  def instantiate(
+      self, methods, method_implementations,
+      multi_method_implementation):
+    """Instantiates the Face layer implementation to be used in a test.
+
+    Args:
+      methods: A sequence of Method objects describing the methods available to
+        be called during the test.
+      method_implementations: A dictionary from group-name pair to
+        face.MethodImplementation object specifying implementation of a method.
+      multi_method_implementation: A face.MultiMethodImplementation or None.
+
+    Returns:
+      A sequence of length three the first element of which is a
+        face.GenericStub, the second element of which is dictionary from groups
+        to face.DynamicStubs affording invocation of the group's methods, and
+        the third element of which is an arbitrary memo object to be kept and
+        passed to destantiate at the conclusion of the test. The returned stubs
+        must be backed by the provided implementations.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def destantiate(self, memo):
+    """Destroys the Face layer implementation under test.
+
+    Args:
+      memo: The object from the third position of the return value of a call to
+        instantiate.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def invocation_metadata(self):
+    """Provides the metadata to be used when invoking a test RPC.
+
+    Returns:
+      An object to use as the supplied-at-invocation-time metadata in a test
+        RPC.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def initial_metadata(self):
+    """Provides the metadata for use as a test RPC's first servicer metadata.
+
+    Returns:
+      An object to use as the from-the-servicer-before-responses metadata in a
+        test RPC.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def terminal_metadata(self):
+    """Provides the metadata for use as a test RPC's second servicer metadata.
+
+    Returns:
+      An object to use as the from-the-servicer-after-all-responses metadata in
+        a test RPC.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def code(self):
+    """Provides the value for use as a test RPC's code.
+
+    Returns:
+      An object to use as the from-the-servicer code in a test RPC.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def details(self):
+    """Provides the value for use as a test RPC's details.
+
+    Returns:
+      An object to use as the from-the-servicer details in a test RPC.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def metadata_transmitted(self, original_metadata, transmitted_metadata):
+    """Identifies whether or not metadata was properly transmitted.
+
+    Args:
+      original_metadata: A metadata value passed to the Face interface
+        implementation under test.
+      transmitted_metadata: The same metadata value after having been
+        transmitted via an RPC performed by the Face interface implementation
+          under test.
+
+    Returns:
+      Whether or not the metadata was properly transmitted by the Face interface
+        implementation under test.
+    """
+    raise NotImplementedError()
diff --git a/src/python/grpcio_tests/tests/unit/framework/interfaces/links/__init__.py b/src/python/grpcio_tests/tests/unit/framework/interfaces/links/__init__.py
new file mode 100644
index 0000000000..7086519106
--- /dev/null
+++ b/src/python/grpcio_tests/tests/unit/framework/interfaces/links/__init__.py
@@ -0,0 +1,30 @@
+# 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/framework/interfaces/links/test_cases.py b/src/python/grpcio_tests/tests/unit/framework/interfaces/links/test_cases.py
new file mode 100644
index 0000000000..608e64119e
--- /dev/null
+++ b/src/python/grpcio_tests/tests/unit/framework/interfaces/links/test_cases.py
@@ -0,0 +1,327 @@
+# 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.
+
+"""Tests of the links interface of RPC Framework."""
+
+# unittest is referenced from specification in this module.
+import abc
+import unittest  # pylint: disable=unused-import
+
+import six
+
+from grpc.framework.interfaces.links import links
+from tests.unit.framework.common import test_constants
+from tests.unit.framework.interfaces.links import test_utilities
+
+
+def at_least_n_payloads_received_predicate(n):
+  def predicate(ticket_sequence):
+    payload_count = 0
+    for ticket in ticket_sequence:
+      if ticket.payload is not None:
+        payload_count += 1
+        if n <= payload_count:
+          return True
+    else:
+      return False
+  return predicate
+
+
+def terminated(ticket_sequence):
+  return ticket_sequence and ticket_sequence[-1].termination is not None
+
+_TRANSMISSION_GROUP = 'test.Group'
+_TRANSMISSION_METHOD = 'TestMethod'
+
+
+class TransmissionTest(six.with_metaclass(abc.ABCMeta)):
+  """Tests ticket transmission between two connected links.
+
+  This class must be mixed into a unittest.TestCase that implements the abstract
+  methods it provides.
+  """
+
+  # This is a unittest.TestCase mix-in.
+  # pylint: disable=invalid-name
+
+  @abc.abstractmethod
+  def create_transmitting_links(self):
+    """Creates two connected links for use in this test.
+
+    Returns:
+      Two links.Links, the first of which will be used on the invocation side
+        of RPCs and the second of which will be used on the service side of
+        RPCs.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def destroy_transmitting_links(self, invocation_side_link, service_side_link):
+    """Destroys the two connected links created for this test.
+
+
+    Args:
+      invocation_side_link: The link used on the invocation side of RPCs in
+        this test.
+      service_side_link: The link used on the service side of RPCs in this
+        test.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def create_invocation_initial_metadata(self):
+    """Creates a value for use as invocation-side initial metadata.
+
+    Returns:
+      A metadata value appropriate for use as invocation-side initial metadata
+        or None if invocation-side initial metadata transmission is not
+        supported by the links under test.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def create_invocation_terminal_metadata(self):
+    """Creates a value for use as invocation-side terminal metadata.
+
+    Returns:
+      A metadata value appropriate for use as invocation-side terminal
+        metadata or None if invocation-side terminal metadata transmission is
+        not supported by the links under test.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def create_service_initial_metadata(self):
+    """Creates a value for use as service-side initial metadata.
+
+    Returns:
+      A metadata value appropriate for use as service-side initial metadata or
+        None if service-side initial metadata transmission is not supported by
+        the links under test.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def create_service_terminal_metadata(self):
+    """Creates a value for use as service-side terminal metadata.
+
+    Returns:
+      A metadata value appropriate for use as service-side terminal metadata or
+        None if service-side terminal metadata transmission is not supported by
+        the links under test.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def create_invocation_completion(self):
+    """Creates values for use as invocation-side code and message.
+
+    Returns:
+      An invocation-side code value and an invocation-side message value.
+        Either or both may be None if invocation-side code and/or
+        invocation-side message transmission is not supported by the links
+        under test.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def create_service_completion(self):
+    """Creates values for use as service-side code and message.
+
+    Returns:
+      A service-side code value and a service-side message value. Either or
+        both may be None if service-side code and/or service-side message
+        transmission is not supported by the links under test.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def assertMetadataTransmitted(self, original_metadata, transmitted_metadata):
+    """Asserts that transmitted_metadata contains original_metadata.
+
+    Args:
+      original_metadata: A metadata object used in this test.
+      transmitted_metadata: A metadata object obtained after transmission
+        through the system under test.
+
+    Raises:
+      AssertionError: if the transmitted_metadata object does not contain
+        original_metadata.
+    """
+    raise NotImplementedError()
+
+  def group_and_method(self):
+    """Returns the group and method used in this test case.
+
+    Returns:
+      A pair of the group and method used in this test case.
+    """
+    return _TRANSMISSION_GROUP, _TRANSMISSION_METHOD
+
+  def serialize_request(self, request):
+    """Serializes a request value used in this test case.
+
+    Args:
+      request: A request value created by this test case.
+
+    Returns:
+      A bytestring that is the serialization of the given request.
+    """
+    return request
+
+  def deserialize_request(self, serialized_request):
+    """Deserializes a request value used in this test case.
+
+    Args:
+      serialized_request: A bytestring that is the serialization of some request
+        used in this test case.
+
+    Returns:
+      The request value encoded by the given bytestring.
+    """
+    return serialized_request
+
+  def serialize_response(self, response):
+    """Serializes a response value used in this test case.
+
+    Args:
+      response: A response value created by this test case.
+
+    Returns:
+      A bytestring that is the serialization of the given response.
+    """
+    return response
+
+  def deserialize_response(self, serialized_response):
+    """Deserializes a response value used in this test case.
+
+    Args:
+      serialized_response: A bytestring that is the serialization of some
+        response used in this test case.
+
+    Returns:
+      The response value encoded by the given bytestring.
+    """
+    return serialized_response
+
+  def _assert_is_valid_metadata_payload_sequence(
+      self, ticket_sequence, payloads, initial_metadata, terminal_metadata):
+    initial_metadata_seen = False
+    seen_payloads = []
+    terminal_metadata_seen = False
+
+    for ticket in ticket_sequence:
+      if ticket.initial_metadata is not None:
+        self.assertFalse(initial_metadata_seen)
+        self.assertFalse(seen_payloads)
+        self.assertFalse(terminal_metadata_seen)
+        self.assertMetadataTransmitted(initial_metadata, ticket.initial_metadata)
+        initial_metadata_seen = True
+
+      if ticket.payload is not None:
+        self.assertFalse(terminal_metadata_seen)
+        seen_payloads.append(ticket.payload)
+
+      if ticket.terminal_metadata is not None:
+        self.assertFalse(terminal_metadata_seen)
+        self.assertMetadataTransmitted(terminal_metadata, ticket.terminal_metadata)
+        terminal_metadata_seen = True
+    self.assertSequenceEqual(payloads, seen_payloads)
+
+  def _assert_is_valid_invocation_sequence(
+      self, ticket_sequence, group, method, payloads, initial_metadata,
+      terminal_metadata, termination):
+    self.assertLess(0, len(ticket_sequence))
+    self.assertEqual(group, ticket_sequence[0].group)
+    self.assertEqual(method, ticket_sequence[0].method)
+    self._assert_is_valid_metadata_payload_sequence(
+        ticket_sequence, payloads, initial_metadata, terminal_metadata)
+    self.assertIs(termination, ticket_sequence[-1].termination)
+
+  def _assert_is_valid_service_sequence(
+      self, ticket_sequence, payloads, initial_metadata, terminal_metadata,
+      code, message, termination):
+    self.assertLess(0, len(ticket_sequence))
+    self._assert_is_valid_metadata_payload_sequence(
+        ticket_sequence, payloads, initial_metadata, terminal_metadata)
+    self.assertEqual(code, ticket_sequence[-1].code)
+    self.assertEqual(message, ticket_sequence[-1].message)
+    self.assertIs(termination, ticket_sequence[-1].termination)
+
+  def setUp(self):
+    self._invocation_link, self._service_link = self.create_transmitting_links()
+    self._invocation_mate = test_utilities.RecordingLink()
+    self._service_mate = test_utilities.RecordingLink()
+    self._invocation_link.join_link(self._invocation_mate)
+    self._service_link.join_link(self._service_mate)
+
+  def tearDown(self):
+    self.destroy_transmitting_links(self._invocation_link, self._service_link)
+
+  def testSimplestRoundTrip(self):
+    """Tests transmission of one ticket in each direction."""
+    invocation_operation_id = object()
+    invocation_payload = b'\x07' * 1023
+    timeout = test_constants.LONG_TIMEOUT
+    invocation_initial_metadata = self.create_invocation_initial_metadata()
+    invocation_terminal_metadata = self.create_invocation_terminal_metadata()
+    invocation_code, invocation_message = self.create_invocation_completion()
+    service_payload = b'\x08' * 1025
+    service_initial_metadata = self.create_service_initial_metadata()
+    service_terminal_metadata = self.create_service_terminal_metadata()
+    service_code, service_message = self.create_service_completion()
+
+    original_invocation_ticket = links.Ticket(
+        invocation_operation_id, 0, _TRANSMISSION_GROUP, _TRANSMISSION_METHOD,
+        links.Ticket.Subscription.FULL, timeout, 0, invocation_initial_metadata,
+        invocation_payload, invocation_terminal_metadata, invocation_code,
+        invocation_message, links.Ticket.Termination.COMPLETION, None)
+    self._invocation_link.accept_ticket(original_invocation_ticket)
+
+    self._service_mate.block_until_tickets_satisfy(
+        at_least_n_payloads_received_predicate(1))
+    service_operation_id = self._service_mate.tickets()[0].operation_id
+
+    self._service_mate.block_until_tickets_satisfy(terminated)
+    self._assert_is_valid_invocation_sequence(
+        self._service_mate.tickets(), _TRANSMISSION_GROUP, _TRANSMISSION_METHOD,
+        (invocation_payload,), invocation_initial_metadata,
+        invocation_terminal_metadata, links.Ticket.Termination.COMPLETION)
+
+    original_service_ticket = links.Ticket(
+        service_operation_id, 0, None, None, links.Ticket.Subscription.FULL,
+        timeout, 0, service_initial_metadata, service_payload,
+        service_terminal_metadata, service_code, service_message,
+        links.Ticket.Termination.COMPLETION, None)
+    self._service_link.accept_ticket(original_service_ticket)
+    self._invocation_mate.block_until_tickets_satisfy(terminated)
+    self._assert_is_valid_service_sequence(
+        self._invocation_mate.tickets(), (service_payload,),
+        service_initial_metadata, service_terminal_metadata, service_code,
+        service_message, links.Ticket.Termination.COMPLETION)
diff --git a/src/python/grpcio_tests/tests/unit/framework/interfaces/links/test_utilities.py b/src/python/grpcio_tests/tests/unit/framework/interfaces/links/test_utilities.py
new file mode 100644
index 0000000000..39c7f2fc63
--- /dev/null
+++ b/src/python/grpcio_tests/tests/unit/framework/interfaces/links/test_utilities.py
@@ -0,0 +1,167 @@
+# 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.
+
+"""State and behavior appropriate for use in tests."""
+
+import logging
+import threading
+import time
+
+from grpc.framework.interfaces.links import links
+from grpc.framework.interfaces.links import utilities
+
+# A more-or-less arbitrary limit on the length of raw data values to be logged.
+_UNCOMFORTABLY_LONG = 48
+
+
+def _safe_for_log_ticket(ticket):
+  """Creates a safe-for-printing-to-the-log ticket for a given ticket.
+
+  Args:
+    ticket: Any links.Ticket.
+
+  Returns:
+    A links.Ticket that is as much as can be equal to the given ticket but
+      possibly features values like the string "<payload of length 972321>" in
+      place of the actual values of the given ticket.
+  """
+  if isinstance(ticket.payload, (basestring,)):
+    payload_length = len(ticket.payload)
+  else:
+    payload_length = -1
+  if payload_length < _UNCOMFORTABLY_LONG:
+    return ticket
+  else:
+    return links.Ticket(
+        ticket.operation_id, ticket.sequence_number,
+        ticket.group, ticket.method, ticket.subscription, ticket.timeout,
+        ticket.allowance, ticket.initial_metadata,
+        '<payload of length {}>'.format(payload_length),
+        ticket.terminal_metadata, ticket.code, ticket.message,
+        ticket.termination, None)
+
+
+class RecordingLink(links.Link):
+  """A Link that records every ticket passed to it."""
+
+  def __init__(self):
+    self._condition = threading.Condition()
+    self._tickets = []
+
+  def accept_ticket(self, ticket):
+    with self._condition:
+      self._tickets.append(ticket)
+      self._condition.notify_all()
+
+  def join_link(self, link):
+    pass
+
+  def block_until_tickets_satisfy(self, predicate):
+    """Blocks until the received tickets satisfy the given predicate.
+
+    Args:
+      predicate: A callable that takes a sequence of tickets and returns a
+        boolean value.
+    """
+    with self._condition:
+      while not predicate(self._tickets):
+        self._condition.wait()
+
+  def tickets(self):
+    """Returns a copy of the list of all tickets received by this Link."""
+    with self._condition:
+      return tuple(self._tickets)
+
+
+class _Pipe(object):
+  """A conduit that logs all tickets passed through it."""
+
+  def __init__(self, name):
+    self._lock = threading.Lock()
+    self._name = name
+    self._left_mate = utilities.NULL_LINK
+    self._right_mate = utilities.NULL_LINK
+
+  def accept_left_to_right_ticket(self, ticket):
+    with self._lock:
+      logging.warning(
+          '%s: moving left to right through %s: %s', time.time(), self._name,
+          _safe_for_log_ticket(ticket))
+      try:
+        self._right_mate.accept_ticket(ticket)
+      except Exception as e:  # pylint: disable=broad-except
+        logging.exception(e)
+
+  def accept_right_to_left_ticket(self, ticket):
+    with self._lock:
+      logging.warning(
+          '%s: moving right to left through %s: %s', time.time(), self._name,
+          _safe_for_log_ticket(ticket))
+      try:
+        self._left_mate.accept_ticket(ticket)
+      except Exception as e:  # pylint: disable=broad-except
+        logging.exception(e)
+
+  def join_left_mate(self, left_mate):
+    with self._lock:
+      self._left_mate = utilities.NULL_LINK if left_mate is None else left_mate
+
+  def join_right_mate(self, right_mate):
+    with self._lock:
+      self._right_mate = (
+          utilities.NULL_LINK if right_mate is None else right_mate)
+
+
+class _Facade(links.Link):
+
+  def __init__(self, accept, join):
+    self._accept = accept
+    self._join = join
+
+  def accept_ticket(self, ticket):
+    self._accept(ticket)
+
+  def join_link(self, link):
+    self._join(link)
+
+
+def logging_links(name):
+  """Creates a conduit that logs all tickets passed through it.
+
+  Args:
+    name: A name to use for the conduit to identify itself in logging output.
+
+  Returns:
+    Two links.Links, the first of which is the "left" side of the conduit
+      and the second of which is the "right" side of the conduit.
+  """
+  pipe = _Pipe(name)
+  left_facade = _Facade(pipe.accept_left_to_right_ticket, pipe.join_left_mate)
+  right_facade = _Facade(pipe.accept_right_to_left_ticket, pipe.join_right_mate)
+  return left_facade, right_facade
diff --git a/src/python/grpcio_tests/tests/unit/resources.py b/src/python/grpcio_tests/tests/unit/resources.py
new file mode 100644
index 0000000000..023cdb155f
--- /dev/null
+++ b/src/python/grpcio_tests/tests/unit/resources.py
@@ -0,0 +1,52 @@
+# 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.
+
+"""Constants and functions for data used in interoperability testing."""
+
+import os
+
+import pkg_resources
+
+_ROOT_CERTIFICATES_RESOURCE_PATH = 'credentials/ca.pem'
+_PRIVATE_KEY_RESOURCE_PATH = 'credentials/server1.key'
+_CERTIFICATE_CHAIN_RESOURCE_PATH = 'credentials/server1.pem'
+
+
+def test_root_certificates():
+  return pkg_resources.resource_string(
+      __name__, _ROOT_CERTIFICATES_RESOURCE_PATH)
+
+
+def private_key():
+  return pkg_resources.resource_string(__name__, _PRIVATE_KEY_RESOURCE_PATH)
+
+
+def certificate_chain():
+  return pkg_resources.resource_string(
+      __name__, _CERTIFICATE_CHAIN_RESOURCE_PATH)
diff --git a/src/python/grpcio_tests/tests/unit/test_common.py b/src/python/grpcio_tests/tests/unit/test_common.py
new file mode 100644
index 0000000000..c8886bf4ca
--- /dev/null
+++ b/src/python/grpcio_tests/tests/unit/test_common.py
@@ -0,0 +1,80 @@
+# 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.
+
+"""Common code used throughout tests of gRPC."""
+
+import collections
+
+import six
+
+INVOCATION_INITIAL_METADATA = (('0', 'abc'), ('1', 'def'), ('2', 'ghi'),)
+SERVICE_INITIAL_METADATA = (('3', 'jkl'), ('4', 'mno'), ('5', 'pqr'),)
+SERVICE_TERMINAL_METADATA = (('6', 'stu'), ('7', 'vwx'), ('8', 'yza'),)
+DETAILS = 'test details'
+
+
+def metadata_transmitted(original_metadata, transmitted_metadata):
+  """Judges whether or not metadata was acceptably transmitted.
+
+  gRPC is allowed to insert key-value pairs into the metadata values given by
+  applications and to reorder key-value pairs with different keys but it is not
+  allowed to alter existing key-value pairs or to reorder key-value pairs with
+  the same key.
+
+  Args:
+    original_metadata: A metadata value used in a test of gRPC. An iterable over
+      iterables of length 2.
+    transmitted_metadata: A metadata value corresponding to original_metadata
+      after having been transmitted via gRPC. An iterable over iterables of
+      length 2.
+
+  Returns:
+     A boolean indicating whether transmitted_metadata accurately reflects
+      original_metadata after having been transmitted via gRPC.
+  """
+  original = collections.defaultdict(list)
+  for key, value in original_metadata:
+    original[key].append(value)
+  transmitted = collections.defaultdict(list)
+  for key, value in transmitted_metadata:
+    transmitted[key].append(value)
+
+  for key, values in six.iteritems(original):
+    transmitted_values = transmitted[key]
+    transmitted_iterator = iter(transmitted_values)
+    try:
+      for value in values:
+        while True:
+          transmitted_value = next(transmitted_iterator)
+          if value == transmitted_value:
+            break
+    except StopIteration:
+      return False
+  else:
+    return True