Fix a defect in RPC Framework Core

On the service-side, an operation isn't successfully completed with
just the conclusion of transmission to the other side; local ingestion
of the status and code must be completed as well before termination
callbacks are called.

src/python/grpcio/grpc/framework/core/_termination.py

-# Copyright 2015, Google Inc.
+# Copyright 2015-2016, Google Inc.
 # All rights reserved.
 #
 # Redistribution and use in source and binary forms, with or without
@@ -46,8 +46,8 @@ def _invocation_completion_predicate(
 
 def _service_completion_predicate(
     unused_emission_complete, transmission_complete, unused_reception_complete,
-    unused_ingestion_complete):
-  return transmission_complete
+    ingestion_complete):
+  return transmission_complete and ingestion_complete
 
 
 class TerminationManager(_interfaces.TerminationManager):

src/python/grpcio/tests/unit/framework/common/test_constants.py

-# Copyright 2015, Google Inc.
+# Copyright 2015-2016, Google Inc.
 # All rights reserved.
 #
 # Redistribution and use in source and binary forms, with or without
@@ -49,5 +49,8 @@ STREAM_LENGTH = 200
 # The size of payloads to transmit in tests.
 PAYLOAD_SIZE = 256 * 1024 + 17
 
+# The parallelism to use in tests of parallel RPCs.
+PARALLELISM = 200
+
 # The size of thread pools to use in tests.
 POOL_SIZE = 10

src/python/grpcio/tests/unit/framework/interfaces/face/_future_invocation_asynchronous_event_service.py

-# Copyright 2015, Google Inc.
+# Copyright 2015-2016, Google Inc.
 # All rights reserved.
 #
 # Redistribution and use in source and binary forms, with or without
@@ -219,6 +219,24 @@ class TestCase(test_coverage.Coverage, unittest.TestCase):
 
         test_messages.verify(second_request, second_response, self)
 
+    for (group, method), test_messages_sequence in (
+        self._digest.unary_unary_messages_sequences.iteritems()):
+      for test_messages in test_messages_sequence:
+        requests = []
+        response_futures = []
+        for _ in range(test_constants.PARALLELISM):
+          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 testParallelInvocations(self):
     for (group, method), test_messages_sequence in (
         self._digest.unary_unary_messages_sequences.iteritems()):