def test_doStart(self):
        """
        L{_WrappingFactory.doStart} passes through to the wrapped factory's
        C{doStart} method, allowing application-specific setup and logging.
        """
        factory = ClientFactory()
        wf = endpoints._WrappingFactory(factory)
        wf.doStart()
        self.assertEqual(1, factory.numPorts)

        L{_WrappingFactory.doStart} passes through to the wrapped factory's
        C{doStart} method, allowing application-specific setup and logging.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/internet/test/test_endpoints.py