def test_userAtHost(self):
        """
        CompleteUserAtHost produces zsh shell-code that completes hostnames or
        a word of the form <username>@<hostname>.
        """
        c = usage.CompleteUserAtHost()
        out = c._shellCode('some-option', usage._ZSH)
        self.assertTrue(out.startswith(':host | user@host:'))

        c = usage.CompleteUserAtHost(descr='some action', repeat=True)
        out = c._shellCode('some-option', usage._ZSH)
        self.assertTrue(out.startswith('*:some action:'))

        CompleteUserAtHost produces zsh shell-code that completes hostnames or
        a word of the form <username>@<hostname>.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/test/test_usage.py