示例#1
0
    def test_request_error_with_prepare_message(self):
        session = self.make_session()
        query = SimpleStatement("SELECT * FROM foobar")
        retry_policy = Mock()
        retry_policy.on_request_error.return_value = (RetryPolicy.RETHROW,
                                                      None)
        message = PrepareMessage(query=query)

        rf = ResponseFuture(session,
                            message,
                            query,
                            1,
                            retry_policy=retry_policy)
        rf._query_retries = 1
        rf.send_request()
        result = Mock(spec=OverloadedErrorMessage)
        result.to_exception.return_value = result
        rf._set_result(None, None, None, result)
        self.assertIsInstance(rf._final_exception, OverloadedErrorMessage)

        rf = ResponseFuture(session,
                            message,
                            query,
                            1,
                            retry_policy=retry_policy)
        rf._query_retries = 1
        rf.send_request()
        result = Mock(spec=ConnectionException)
        rf._set_result(None, None, None, result)
        self.assertIsInstance(rf._final_exception, ConnectionException)
    def test_errback(self):
        session = self.make_session()
        pool = session._pools.get.return_value
        connection = Mock(spec=Connection)
        pool.borrow_connection.return_value = (connection, 1)

        query = SimpleStatement("INSERT INFO foo (a, b) VALUES (1, 2)")
        message = QueryMessage(query=query,
                               consistency_level=ConsistencyLevel.ONE)

        rf = ResponseFuture(session, message, query, 1)
        rf._query_retries = 1
        rf.send_request()

        rf.add_errback(self.assertIsInstance, Exception)

        result = Mock(spec=UnavailableErrorMessage,
                      info={
                          "required_replicas": 2,
                          "alive_replicas": 1,
                          "consistency": 1
                      })
        result.to_exception.return_value = Exception()

        rf._set_result(None, None, None, result)
        self.assertRaises(Exception, rf.result)

        # this should get called immediately now that the error is set
        rf.add_errback(self.assertIsInstance, Exception)
    def test_add_callbacks(self):
        session = self.make_session()
        query = SimpleStatement("INSERT INFO foo (a, b) VALUES (1, 2)")
        query.retry_policy = Mock()
        query.retry_policy.on_unavailable.return_value = (RetryPolicy.RETHROW, None)
        message = QueryMessage(query=query, consistency_level=ConsistencyLevel.ONE)

        # test errback
        rf = ResponseFuture(session, message, query)
        rf.send_request()

        rf.add_callbacks(
            callback=self.assertEquals, callback_args=([{'col': 'val'}],),
            errback=self.assertIsInstance, errback_args=(Exception,))

        result = Mock(spec=UnavailableErrorMessage, info={})
        rf._set_result(result)
        self.assertRaises(Exception, rf.result)

        # test callback
        rf = ResponseFuture(session, message, query)
        rf.send_request()

        rf.add_callbacks(
            callback=self.assertEquals, callback_args=([{'col': 'val'}],),
            errback=self.assertIsInstance, errback_args=(Exception,))

        response = Mock(spec=ResultMessage, kind=ResultMessage.KIND_ROWS, results=[{'col': 'val'}])
        rf._set_result(response)
        self.assertEqual(rf.result(), [{'col': 'val'}])
    def test_add_callbacks(self):
        session = self.make_session()
        query = SimpleStatement("INSERT INFO foo (a, b) VALUES (1, 2)")
        query.retry_policy = Mock()
        query.retry_policy.on_unavailable.return_value = (RetryPolicy.RETHROW, None)
        message = QueryMessage(query=query, consistency_level=ConsistencyLevel.ONE)

        # test errback
        rf = ResponseFuture(session, message, query, 1)
        rf.send_request()

        rf.add_callbacks(
            callback=self.assertEqual, callback_args=([{'col': 'val'}],),
            errback=self.assertIsInstance, errback_args=(Exception,))

        result = Mock(spec=UnavailableErrorMessage, info={})
        rf._set_result(result)
        self.assertRaises(Exception, rf.result)

        # test callback
        rf = ResponseFuture(session, message, query, 1)
        rf.send_request()

        callback = Mock()
        expected_result = [{'col': 'val'}]
        arg = "positional"
        kwargs = {'one': 1, 'two': 2}
        rf.add_callbacks(
            callback=callback, callback_args=(arg,), callback_kwargs=kwargs,
            errback=self.assertIsInstance, errback_args=(Exception,))

        rf._set_result(self.make_mock_response(expected_result))
        self.assertEqual(rf.result(), expected_result)

        callback.assert_called_once_with(expected_result, arg, **kwargs)
    def test_multiple_errbacks(self):
        session = self.make_session()
        pool = session._pools.get.return_value
        connection = Mock(spec=Connection)
        pool.borrow_connection.return_value = (connection, 1)

        query = SimpleStatement("INSERT INFO foo (a, b) VALUES (1, 2)")
        query.retry_policy = Mock()
        query.retry_policy.on_unavailable.return_value = (RetryPolicy.RETHROW, None)
        message = QueryMessage(query=query, consistency_level=ConsistencyLevel.ONE)

        rf = ResponseFuture(session, message, query, 1)
        rf.send_request()

        callback = Mock()
        arg = "positional"
        kwargs = {'one': 1, 'two': 2}
        rf.add_errback(callback, arg, **kwargs)

        callback2 = Mock()
        arg2 = "another"
        kwargs2 = {'three': 3, 'four': 4}
        rf.add_errback(callback2, arg2, **kwargs2)

        expected_exception = Unavailable("message", 1, 2, 3)
        result = Mock(spec=UnavailableErrorMessage, info={'something': 'here'})
        result.to_exception.return_value = expected_exception
        rf._set_result(result)
        self.assertRaises(Exception, rf.result)

        callback.assert_called_once_with(expected_exception, arg, **kwargs)
        callback2.assert_called_once_with(expected_exception, arg2, **kwargs2)
    def test_multiple_errbacks(self):
        session = self.make_session()
        pool = session._pools.get.return_value
        connection = Mock(spec=Connection)
        pool.borrow_connection.return_value = (connection, 1)

        query = SimpleStatement("INSERT INFO foo (a, b) VALUES (1, 2)")
        query.retry_policy = Mock()
        query.retry_policy.on_unavailable.return_value = (RetryPolicy.RETHROW,
                                                          None)
        message = QueryMessage(query=query,
                               consistency_level=ConsistencyLevel.ONE)

        rf = ResponseFuture(session, message, query)
        rf.send_request()

        callback = Mock()
        arg = "positional"
        kwargs = {'one': 1, 'two': 2}
        rf.add_errback(callback, arg, **kwargs)

        callback2 = Mock()
        arg2 = "another"
        kwargs2 = {'three': 3, 'four': 4}
        rf.add_errback(callback2, arg2, **kwargs2)

        expected_exception = Unavailable("message", 1, 2, 3)
        result = Mock(spec=UnavailableErrorMessage, info={'something': 'here'})
        result.to_exception.return_value = expected_exception
        rf._set_result(result)
        self.assertRaises(Exception, rf.result)

        callback.assert_called_once_with(expected_exception, arg, **kwargs)
        callback2.assert_called_once_with(expected_exception, arg2, **kwargs2)
    def test_retry_policy_says_retry(self):
        session = self.make_session()
        pool = session._pools.get.return_value
        query = SimpleStatement("INSERT INFO foo (a, b) VALUES (1, 2)")
        query.retry_policy = Mock()
        query.retry_policy.on_unavailable.return_value = (RetryPolicy.RETRY,
                                                          ConsistencyLevel.ONE)
        message = QueryMessage(query=query,
                               consistency_level=ConsistencyLevel.QUORUM)

        rf = ResponseFuture(session, message, query)
        rf.send_request()

        rf.session._pools.get.assert_called_once_with('ip1')
        pool.borrow_connection.assert_called_once_with(timeout=ANY)
        connection = pool.borrow_connection.return_value
        connection.send_msg.assert_called_once_with(rf.message, cb=ANY)

        result = Mock(spec=UnavailableErrorMessage, info={})
        rf._set_result(result)

        session.submit.assert_called_once_with(rf._retry_task, True)
        self.assertEqual(1, rf._query_retries)

        # simulate the executor running this
        rf._retry_task(True)

        # it should try again with the same host since this was
        # an UnavailableException
        rf.session._pools.get.assert_called_with('ip1')
        pool.borrow_connection.assert_called_with(timeout=ANY)
        connection = pool.borrow_connection.return_value
        connection.send_msg.assert_called_with(rf.message, cb=ANY)
    def test_add_callbacks(self):
        session = self.make_session()
        query = SimpleStatement("INSERT INFO foo (a, b) VALUES (1, 2)")
        query.retry_policy = Mock()
        query.retry_policy.on_unavailable.return_value = (RetryPolicy.RETHROW, None)
        message = QueryMessage(query=query, consistency_level=ConsistencyLevel.ONE)

        # test errback
        rf = ResponseFuture(session, message, query, 1)
        rf.send_request()

        rf.add_callbacks(
            callback=self.assertEqual, callback_args=([{'col': 'val'}],),
            errback=self.assertIsInstance, errback_args=(Exception,))

        result = Mock(spec=UnavailableErrorMessage, info={})
        rf._set_result(None, None, None, result)
        self.assertRaises(Exception, rf.result)

        # test callback
        rf = ResponseFuture(session, message, query, 1)
        rf.send_request()

        callback = Mock()
        expected_result = [{'col': 'val'}]
        arg = "positional"
        kwargs = {'one': 1, 'two': 2}
        rf.add_callbacks(
            callback=callback, callback_args=(arg,), callback_kwargs=kwargs,
            errback=self.assertIsInstance, errback_args=(Exception,))

        rf._set_result(None, None, None, self.make_mock_response(expected_result))
        self.assertEqual(rf.result(), expected_result)

        callback.assert_called_once_with(expected_result, arg, **kwargs)
示例#9
0
    def test_add_callbacks(self):
        session = self.make_session()
        query = SimpleStatement("INSERT INFO foo (a, b) VALUES (1, 2)")
        query.retry_policy = Mock()
        query.retry_policy.on_unavailable.return_value = (RetryPolicy.RETHROW, None)
        message = QueryMessage(query=query, consistency_level=ConsistencyLevel.ONE)

        # test errback
        rf = ResponseFuture(session, message, query)
        rf.send_request()

        rf.add_callbacks(
            callback=self.assertEqual, callback_args=([{'col': 'val'}],),
            errback=self.assertIsInstance, errback_args=(Exception,))

        result = Mock(spec=UnavailableErrorMessage, info={})
        rf._set_result(result)
        self.assertRaises(Exception, rf.result)

        # test callback
        rf = ResponseFuture(session, message, query)
        rf.send_request()

        rf.add_callbacks(
            callback=self.assertEqual, callback_args=([{'col': 'val'}],),
            errback=self.assertIsInstance, errback_args=(Exception,))

        rf._set_result(self.make_mock_response([{'col': 'val'}]))
        self.assertEqual(rf.result(), [{'col': 'val'}])
    def test_retry_policy_says_retry(self):
        session = self.make_session()
        pool = session._pools.get.return_value
        query = SimpleStatement("INSERT INFO foo (a, b) VALUES (1, 2)")
        query.retry_policy = Mock()
        query.retry_policy.on_unavailable.return_value = (RetryPolicy.RETRY, ConsistencyLevel.ONE)
        message = QueryMessage(query=query, consistency_level=ConsistencyLevel.QUORUM)

        rf = ResponseFuture(session, message, query)
        rf.send_request()

        rf.session._pools.get.assert_called_once_with('ip1')
        pool.borrow_connection.assert_called_once_with(timeout=ANY)
        connection = pool.borrow_connection.return_value
        connection.send_msg.assert_called_once_with(rf.message, cb=ANY)

        result = Mock(spec=UnavailableErrorMessage, info={})
        rf._set_result(result)

        session.submit.assert_called_once_with(rf._retry_task, True)
        self.assertEqual(1, rf._query_retries)

        # simulate the executor running this
        rf._retry_task(True)

        # it should try again with the same host since this was
        # an UnavailableException
        rf.session._pools.get.assert_called_with('ip1')
        pool.borrow_connection.assert_called_with(timeout=ANY)
        connection = pool.borrow_connection.return_value
        connection.send_msg.assert_called_with(rf.message, cb=ANY)
示例#11
0
    def test_retry_policy_says_retry(self):
        session = self.make_session()
        pool = session._pools.get.return_value

        query = SimpleStatement("INSERT INFO foo (a, b) VALUES (1, 2)")
        message = QueryMessage(query=query,
                               consistency_level=ConsistencyLevel.QUORUM)

        connection = Mock(spec=Connection)
        pool.borrow_connection.return_value = (connection, 1)

        retry_policy = Mock()
        retry_policy.on_unavailable.return_value = (RetryPolicy.RETRY,
                                                    ConsistencyLevel.ONE)

        rf = ResponseFuture(session,
                            message,
                            query,
                            1,
                            retry_policy=retry_policy)
        rf.send_request()

        rf.session._pools.get.assert_called_once_with('ip1')
        pool.borrow_connection.assert_called_once_with(timeout=ANY,
                                                       routing_key=ANY)
        connection.send_msg.assert_called_once_with(
            rf.message,
            1,
            cb=ANY,
            encoder=ProtocolHandler.encode_message,
            decoder=ProtocolHandler.decode_message,
            result_metadata=[])

        result = Mock(spec=UnavailableErrorMessage, info={})
        host = Mock()
        rf._set_result(host, None, None, result)

        session.submit.assert_called_once_with(rf._retry_task, True, host)
        self.assertEqual(1, rf._query_retries)

        connection = Mock(spec=Connection)
        pool.borrow_connection.return_value = (connection, 2)

        # simulate the executor running this
        rf._retry_task(True, host)

        # it should try again with the same host since this was
        # an UnavailableException
        rf.session._pools.get.assert_called_with(host)
        pool.borrow_connection.assert_called_with(timeout=ANY, routing_key=ANY)
        connection.send_msg.assert_called_with(
            rf.message,
            2,
            cb=ANY,
            encoder=ProtocolHandler.encode_message,
            decoder=ProtocolHandler.decode_message,
            result_metadata=[])
    def test_write_timeout_error_message(self):
        session = self.make_session()
        query = SimpleStatement("INSERT INFO foo (a, b) VALUES (1, 2)")
        message = QueryMessage(query=query, consistency_level=ConsistencyLevel.ONE)

        rf = ResponseFuture(session, message, query, 1)
        rf.send_request()

        result = Mock(spec=WriteTimeoutErrorMessage, info={"write_type": 1, "required_responses":2,
                                                           "received_responses":1, "consistency": 1})
        rf._set_result(None, None, None, result)
        self.assertRaises(Exception, rf.result)
    def test_write_timeout_error_message(self):
        session = self.make_session()
        query = SimpleStatement("INSERT INFO foo (a, b) VALUES (1, 2)")
        query.retry_policy = Mock()
        query.retry_policy.on_write_timeout.return_value = (RetryPolicy.RETHROW, None)
        message = QueryMessage(query=query, consistency_level=ConsistencyLevel.ONE)

        rf = ResponseFuture(session, message, query)
        rf.send_request()

        result = Mock(spec=WriteTimeoutErrorMessage, info={})
        rf._set_result(result)
        self.assertRaises(Exception, rf.result)
    def test_retry_policy_says_ignore(self):
        session = self.make_session()
        query = SimpleStatement("INSERT INFO foo (a, b) VALUES (1, 2)")
        query.retry_policy = Mock()
        query.retry_policy.on_unavailable.return_value = (RetryPolicy.IGNORE, None)
        message = QueryMessage(query=query, consistency_level=ConsistencyLevel.ONE)

        rf = ResponseFuture(session, message, query)
        rf.send_request()

        result = Mock(spec=UnavailableErrorMessage, info={})
        rf._set_result(result)
        self.assertEqual(None, rf.result())
    def test_read_timeout_error_message(self):
        session = self.make_session()
        query = SimpleStatement("SELECT * FROM foo")
        message = QueryMessage(query=query, consistency_level=ConsistencyLevel.ONE)

        rf = ResponseFuture(session, message, query, 1)
        rf.send_request()

        result = Mock(spec=ReadTimeoutErrorMessage, info={"data_retrieved": "", "required_responses":2,
                                                           "received_responses":1, "consistency": 1})
        rf._set_result(None, None, None, result)

        self.assertRaises(Exception, rf.result)
示例#16
0
    def test_retry_policy_says_ignore(self):
        session = self.make_session()
        query = SimpleStatement("INSERT INFO foo (a, b) VALUES (1, 2)")
        query.retry_policy = Mock()
        query.retry_policy.on_unavailable.return_value = (RetryPolicy.IGNORE, None)
        message = QueryMessage(query=query, consistency_level=ConsistencyLevel.ONE)

        rf = ResponseFuture(session, message, query)
        rf.send_request()

        result = Mock(spec=UnavailableErrorMessage, info={})
        rf._set_result(result)
        self.assertEqual(None, rf.result())
示例#17
0
    def test_write_timeout_error_message(self):
        session = self.make_session()
        query = SimpleStatement("INSERT INFO foo (a, b) VALUES (1, 2)")
        query.retry_policy = Mock()
        query.retry_policy.on_write_timeout.return_value = (RetryPolicy.RETHROW, None)
        message = QueryMessage(query=query, consistency_level=ConsistencyLevel.ONE)

        rf = ResponseFuture(session, message, query)
        rf.send_request()

        result = Mock(spec=WriteTimeoutErrorMessage, info={})
        rf._set_result(result)
        self.assertRaises(Exception, rf.result)
    def test_unavailable_error_message(self):
        session = self.make_session()
        query = SimpleStatement("INSERT INFO foo (a, b) VALUES (1, 2)")
        query.retry_policy = Mock()
        query.retry_policy.on_unavailable.return_value = (RetryPolicy.RETHROW, None)
        message = QueryMessage(query=query, consistency_level=ConsistencyLevel.ONE)

        rf = ResponseFuture(session, message, query, 1)
        rf._query_retries = 1
        rf.send_request()

        result = Mock(spec=UnavailableErrorMessage, info={"required_replicas":2, "alive_replicas": 1, "consistency": 1})
        rf._set_result(None, None, None, result)
        self.assertRaises(Exception, rf.result)
    def test_read_timeout_error_message(self):
        session = self.make_session()
        query = SimpleStatement("SELECT * FROM foo")
        query.retry_policy = Mock()
        query.retry_policy.on_read_timeout.return_value = (RetryPolicy.RETHROW, None)
        message = QueryMessage(query=query, consistency_level=ConsistencyLevel.ONE)

        rf = ResponseFuture(session, message, query, 1)
        rf.send_request()

        result = Mock(spec=ReadTimeoutErrorMessage, info={})
        rf._set_result(result)

        self.assertRaises(Exception, rf.result)
    def test_read_timeout_error_message(self):
        session = self.make_session()
        query = SimpleStatement("SELECT * FROM foo")
        query.retry_policy = Mock()
        query.retry_policy.on_read_timeout.return_value = (RetryPolicy.RETHROW, None)
        message = QueryMessage(query=query, consistency_level=ConsistencyLevel.ONE)

        rf = ResponseFuture(session, message, query, 1)
        rf.send_request()

        result = Mock(spec=ReadTimeoutErrorMessage, info={})
        rf._set_result(None, None, None, result)

        self.assertRaises(Exception, rf.result)
示例#21
0
    def test_add_callbacks(self):
        session = self.make_session()
        query = SimpleStatement("INSERT INFO foo (a, b) VALUES (1, 2)")
        message = QueryMessage(query=query,
                               consistency_level=ConsistencyLevel.ONE)

        # test errback
        rf = ResponseFuture(session, message, query, 1)
        rf._query_retries = 1
        rf.send_request()

        rf.add_callbacks(callback=self.assertEqual,
                         callback_args=([{
                             'col': 'val'
                         }], ),
                         errback=self.assertIsInstance,
                         errback_args=(Exception, ))

        result = Mock(spec=UnavailableErrorMessage,
                      info={
                          "required_replicas": 2,
                          "alive_replicas": 1,
                          "consistency": 1
                      })
        result.to_exception.return_value = Exception()
        rf._set_result(None, None, None, result)
        self.assertRaises(Exception, rf.result)

        # test callback
        rf = ResponseFuture(session, message, query, 1)
        rf.send_request()

        callback = Mock()
        expected_result = (object(), object())
        arg = "positional"
        kwargs = {'one': 1, 'two': 2}
        rf.add_callbacks(callback=callback,
                         callback_args=(arg, ),
                         callback_kwargs=kwargs,
                         errback=self.assertIsInstance,
                         errback_args=(Exception, ))

        rf._set_result(
            None, None, None,
            self.make_mock_response(expected_result[0], expected_result[1]))
        self.assertEqual(rf.result()[0], expected_result)

        callback.assert_called_once_with([expected_result], arg, **kwargs)
    def test_errback(self):
        session = self.make_session()
        query = SimpleStatement("INSERT INFO foo (a, b) VALUES (1, 2)")
        query.retry_policy = Mock()
        query.retry_policy.on_unavailable.return_value = (RetryPolicy.RETHROW, None)
        message = QueryMessage(query=query, consistency_level=ConsistencyLevel.ONE)

        rf = ResponseFuture(session, message, query)
        rf.send_request()

        rf.add_errback(self.assertIsInstance, Exception)

        result = Mock(spec=UnavailableErrorMessage, info={})
        rf._set_result(result)
        self.assertRaises(Exception, rf.result)

        # this should get called immediately now that the error is set
        rf.add_errback(self.assertIsInstance, Exception)
    def test_write_timeout_error_message(self):
        session = self.make_session()
        query = SimpleStatement("INSERT INFO foo (a, b) VALUES (1, 2)")
        message = QueryMessage(query=query,
                               consistency_level=ConsistencyLevel.ONE)

        rf = ResponseFuture(session, message, query, 1)
        rf.send_request()

        result = Mock(spec=WriteTimeoutErrorMessage,
                      info={
                          "write_type": 1,
                          "required_responses": 2,
                          "received_responses": 1,
                          "consistency": 1
                      })
        rf._set_result(None, None, None, result)
        self.assertRaises(Exception, rf.result)
    def test_read_timeout_error_message(self):
        session = self.make_session()
        query = SimpleStatement("SELECT * FROM foo")
        message = QueryMessage(query=query,
                               consistency_level=ConsistencyLevel.ONE)

        rf = ResponseFuture(session, message, query, 1)
        rf.send_request()

        result = Mock(spec=ReadTimeoutErrorMessage,
                      info={
                          "data_retrieved": "",
                          "required_responses": 2,
                          "received_responses": 1,
                          "consistency": 1
                      })
        rf._set_result(None, None, None, result)

        self.assertRaises(Exception, rf.result)
    def test_errback(self):
        session = self.make_session()
        query = SimpleStatement("INSERT INFO foo (a, b) VALUES (1, 2)")
        query.retry_policy = Mock()
        query.retry_policy.on_unavailable.return_value = (RetryPolicy.RETHROW,
                                                          None)
        message = QueryMessage(query=query,
                               consistency_level=ConsistencyLevel.ONE)

        rf = ResponseFuture(session, message, query)
        rf.send_request()

        rf.add_errback(self.assertIsInstance, Exception)

        result = Mock(spec=UnavailableErrorMessage, info={})
        rf._set_result(result)
        self.assertRaises(Exception, rf.result)

        # this should get called immediately now that the error is set
        rf.add_errback(self.assertIsInstance, Exception)
    def test_unavailable_error_message(self):
        session = self.make_session()
        query = SimpleStatement("INSERT INFO foo (a, b) VALUES (1, 2)")
        query.retry_policy = Mock()
        query.retry_policy.on_unavailable.return_value = (RetryPolicy.RETHROW,
                                                          None)
        message = QueryMessage(query=query,
                               consistency_level=ConsistencyLevel.ONE)

        rf = ResponseFuture(session, message, query, 1)
        rf._query_retries = 1
        rf.send_request()

        result = Mock(spec=UnavailableErrorMessage,
                      info={
                          "required_replicas": 2,
                          "alive_replicas": 1,
                          "consistency": 1
                      })
        rf._set_result(None, None, None, result)
        self.assertRaises(Exception, rf.result)
    def test_errback(self):
        session = self.make_session()
        pool = session._pools.get.return_value
        connection = Mock(spec=Connection)
        pool.borrow_connection.return_value = (connection, 1)

        query = SimpleStatement("INSERT INFO foo (a, b) VALUES (1, 2)")
        message = QueryMessage(query=query, consistency_level=ConsistencyLevel.ONE)

        rf = ResponseFuture(session, message, query, 1)
        rf._query_retries = 1
        rf.send_request()

        rf.add_errback(self.assertIsInstance, Exception)

        result = Mock(spec=UnavailableErrorMessage, info={"required_replicas":2, "alive_replicas": 1, "consistency": 1})
        result.to_exception.return_value = Exception()

        rf._set_result(None, None, None, result)
        self.assertRaises(Exception, rf.result)

        # this should get called immediately now that the error is set
        rf.add_errback(self.assertIsInstance, Exception)