fix test connection observer
@@ -28,6 +28,7 @@ def test_calling_start_on_connection_observer_returns_itself(do_nothing_connecti
connection_observer = do_nothing_connection_observer__for_major_base_class
connection_observer.connection = connection_to_remote.moler_connection
assert connection_observer == connection_observer.start()
+ connection_observer.cancel()
# str representation of class instances may be specific for given class - means: each derived class
