def test_SRVNoResultUnknownServiceDefaultPort(self):
        """
        connectTCP gets called with default port if the service is not defined.
        """
        self.connector = srvconnect.SRVConnector(self.reactor,
                                                 'thisbetternotexist',
                                                 'example.org', self.factory,
                                                 defaultPort=5222)

        client.theResolver.failure = ServiceNameUnknownError()
        self.connector.connect()

        self.assertIsNone(self.factory.reason)
        self.assertEqual(
            self.reactor.tcpClients.pop()[:2], ('example.org', 5222))

        connectTCP gets called with default port if the service is not defined.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/names/test/test_srvconnect.py