def test_exec(self):
        """
        Test that we can use whatever client to send the command "echo goodbye"
        to the Conch server. Make sure we receive "goodbye" back from the
        server.
        """
        d = self.execute('echo goodbye', ConchTestOpenSSHProcess())
        return d.addCallback(self.assertEqual, b'goodbye\n')

        Test that we can use whatever client to send the command "echo goodbye"
        to the Conch server. Make sure we receive "goodbye" back from the
        server.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/conch/test/test_conch.py