def test_SERVICE_REQUEST(self):
        """
        Test that the SERVICE_REQUEST message requests and starts a
        service.
        """
        self.proto.ssh_SERVICE_REQUEST(common.NS(b'ssh-userauth'))
        self.assertEqual(self.packets, [(transport.MSG_SERVICE_ACCEPT,
                                         common.NS(b'ssh-userauth'))])
        self.assertEqual(self.proto.service.name, b'MockService')

        Test that the SERVICE_REQUEST message requests and starts a
        service.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/conch/test/test_transport.py