def test_hostValueNonStandardHTTP(self):
        """
        When passed a scheme of C{'http'} and a port other than C{80},
        L{Agent._computeHostValue} returns a string giving the
        host passed to it joined together with the port number by C{":"}.
        """
        self.assertEqual(
            self.agent._computeHostValue(b'http', b'example.com', 54321),
            b'example.com:54321')

        When passed a scheme of C{'http'} and a port other than C{80},
        L{Agent._computeHostValue} returns a string giving the
        host passed to it joined together with the port number by C{":"}.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/web/test/test_agent.py