def test_quiet(self):
        """
        L{TLSMemoryBIOFactory.doStart} and L{TLSMemoryBIOFactory.doStop} do
        not log any messages.
        """
        contextFactory = ServerTLSContext()

        logs = []
        logger = logs.append
        log.addObserver(logger)
        self.addCleanup(log.removeObserver, logger)
        wrappedFactory = ServerFactory()
        # Disable logging on the wrapped factory:
        wrappedFactory.doStart = lambda: None
        wrappedFactory.doStop = lambda: None
        factory = TLSMemoryBIOFactory(contextFactory, False, wrappedFactory)
        factory.doStart()
        factory.doStop()
        self.assertEqual(logs, [])

        L{TLSMemoryBIOFactory.doStart} and L{TLSMemoryBIOFactory.doStop} do
        not log any messages.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/protocols/test/test_tls.py