def test_warn(self):
        """
        L{ConsoleUI.warn} should output a message to the console object.
        """
        self.ui.warn("Test message.")
        self.assertEqual(["Test message."], self.fakeFile.outchunks)
        self.assertTrue(self.fakeFile.closed)

        L{ConsoleUI.warn} should output a message to the console object.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/conch/test/test_knownhosts.py