def test_HTTPChannelUnregistersSelfWhenTimingOut(self):
        """
        L{HTTPChannel} unregisters itself when it times out a connection.
        """
        clock = Clock()
        transport = StringTransport()
        channel = http.HTTPChannel()

        # Patch the channel's callLater method.
        channel.timeOut = 100
        channel.callLater = clock.callLater
        channel.makeConnection(transport)

        # Tick the clock forward almost to the timeout.
        clock.advance(99)
        self.assertIs(transport.producer, channel)
        self.assertIs(transport.streaming, True)

        # Fire the timeout.
        clock.advance(1)
        self.assertIs(transport.producer, None)
        self.assertIs(transport.streaming, None)

        L{HTTPChannel} unregisters itself when it times out a connection.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/web/test/test_http.py