def test_fire_on_stop(self):
        result = main_for_service(self.reactor, self.service)
        self._shutdown_reactor(self.reactor)
        self.assertIs(None, self.successResultOf(result))
The ``Deferred`` returned by ``main_for_service`` fires with ``None``
dataset/ETHPy150Open ClusterHQ/flocker/flocker/common/test/test_script.py/MainForServiceTests.test_fire_on_stop