def test_wrappingBehavior(self):
        """
        Any modifications performed by the underlying L{ProtocolWrapper}
        propagate through to the wrapped L{Protocol}.
        """
        connecting = self.wrapper.connect(self.factory)
        pump = self.completer.succeedOnce()
        proto = self.successResultOf(connecting)
        pump.server.transport.write(b'5:hello,')
        pump.flush()
        self.assertEqual(proto.strings, [b'HELLO'])

        Any modifications performed by the underlying L{ProtocolWrapper}
        propagate through to the wrapped L{Protocol}.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/internet/test/test_endpoints.py