def test_list(self):
        """
        When L{finger.Finger} receives a blank line, it responds with a message
        rejecting the request for all online users.
        """
        self.protocol.dataReceived(b"\r\n")
        self.assertEqual(
            self.transport.value(),
            b"Finger online list denied\n")

        When L{finger.Finger} receives a blank line, it responds with a message
        rejecting the request for all online users.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/test/test_finger.py