def test_badConnect(self):
        """
        A call to the transport's connect method fails with an
        L{InvalidAddressError} when a non-IP address is passed as the host
        value.

        A call to a transport's connect method fails with a L{RuntimeError}
        when the transport is already connected.
        """
        client = GoodClient()
        port = reactor.listenUDP(0, client, interface="127.0.0.1")
        self.assertRaises(error.InvalidAddressError, client.transport.connect,
                          "localhost", 80)
        client.transport.connect("127.0.0.1", 80)
        self.assertRaises(RuntimeError, client.transport.connect,
                          "127.0.0.1", 80)
        return port.stopListening()

        A call to the transport's connect method fails with an
        L{InvalidAddressError} when a non-IP address is passed as the host
        value.

        A call to a transport's connect method fails with a L{RuntimeError}
        when the transport is already connected.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/test/test_udp.py