def test_SRVNoResultUnknownServiceNoDefaultPort(self):
        """
        Connect fails on no result, unknown service and no default port.
        """
        self.connector = srvconnect.SRVConnector(self.reactor,
                                                 'thisbetternotexist',
                                                 'example.org', self.factory)

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

        self.assertTrue(self.factory.reason.check(ServiceNameUnknownError))

        Connect fails on no result, unknown service and no default port.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/names/test/test_srvconnect.py