def test_abortAuthentication(self):
        """
        Test that a challenge/response sequence can be aborted by the client.
        """
        loginArgs = []
        self.server.portal = self.portalFactory(loginArgs)

        self.server.dataReceived(b'EHLO\r\n')
        self.server.dataReceived(b'AUTH LOGIN\r\n')

        self.assertServerResponse(
            b'*\r\n',
            [b'501 Authentication aborted'])

        Test that a challenge/response sequence can be aborted by the client.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/mail/test/test_smtp.py