def inner(return_value=None, side_effect=None):
stub = stub_connection(return_value=return_value,
side_effect=side_effect)
context_manager = MagicMock()
context_manager.__aenter__ = CoroutineMock(return_value=stub)
context_manager.__aexit__ = CoroutineMock()
manager = MagicMock()
manager.new_connection = Mock(return_value=context_manager)
manager.connection_stub = stub
return manager
