def test_GenericHTTPChannelPropagatesCallLater(self):
        """
        If C{callLater} is patched onto the L{http._GenericHTTPChannelProtocol}
        then we need to propagate it through to the backing channel.
        """
        clock = Clock()
        factory = http.HTTPFactory(reactor=clock)
        protocol = factory.buildProtocol(None)

        self.assertEqual(protocol.callLater, clock.callLater)
        self.assertEqual(protocol._channel.callLater, clock.callLater)

        If C{callLater} is patched onto the L{http._GenericHTTPChannelProtocol}
        then we need to propagate it through to the backing channel.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/web/test/test_http.py