Test coverage for callbacks added to Face futures

src/python/grpcio_test/grpc_test/framework/interfaces/face/_future_invocation_asynchronous_event_service.py

@@ -72,6 +72,36 @@ class _PauseableIterator(object):
     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(test_coverage.Coverage, unittest.TestCase):
   """A test of the Face layer of RPC Framework.
 
@@ -112,12 +142,15 @@ class TestCase(test_coverage.Coverage, unittest.TestCase):
         self._digest.unary_unary_messages_sequences.iteritems()):
       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 (
@@ -137,15 +170,19 @@ class TestCase(test_coverage.Coverage, unittest.TestCase):
       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 = response_future.result()
+          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 (
@@ -208,12 +245,15 @@ class TestCase(test_coverage.Coverage, unittest.TestCase):
         self._digest.unary_unary_messages_sequences.iteritems()):
       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())
 
@@ -236,12 +276,15 @@ class TestCase(test_coverage.Coverage, unittest.TestCase):
         self._digest.stream_unary_messages_sequences.iteritems()):
       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())
 
@@ -264,10 +307,13 @@ class TestCase(test_coverage.Coverage, unittest.TestCase):
         self._digest.unary_unary_messages_sequences.iteritems()):
       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):
@@ -290,10 +336,13 @@ class TestCase(test_coverage.Coverage, unittest.TestCase):
         self._digest.stream_unary_messages_sequences.iteritems()):
       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):
@@ -316,11 +365,14 @@ class TestCase(test_coverage.Coverage, unittest.TestCase):
         self._digest.unary_unary_messages_sequences.iteritems()):
       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
@@ -350,11 +402,14 @@ class TestCase(test_coverage.Coverage, unittest.TestCase):
         self._digest.stream_unary_messages_sequences.iteritems()):
       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