def test_loggerComponentBeatsLegacyLoggerComponent(self):
        """
        A L{ILogObserver} takes precedence over a L{LegacyILogObserver}
        component set on Application.
        """
        nonlogs = []
        observer = self._makeObserver()
        application = Componentized()
        application.setComponent(ILogObserver, observer)
        application.setComponent(LegacyILogObserver, nonlogs.append)

        logger = app.AppLogger({})
        logger.start(application)

        self._checkObserver(observer)
        self.assertEqual(nonlogs, [])

        A L{ILogObserver} takes precedence over a L{LegacyILogObserver}
        component set on Application.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/test/test_twistd.py