def test_doctestError(self):
        """
        A problem encountered while running a doctest is reported in the output
        stream with a I{FAIL} or I{ERROR} tag along with a summary of what
        problem was encountered and the ID of the test.
        """
        from twisted.trial.test import erroneous
        suite = unittest.decorate(
            self.loader.loadDoctests(erroneous), itrial.ITestCase)
        output = self.getOutput(suite)
        path = 'twisted.trial.test.erroneous.unexpectedException'
        for substring in ['1/0', 'ZeroDivisionError',
                          'Exception raised:', path]:
            self.assertSubstring(substring, output)
        self.assertTrue(re.search('Fail(ed|ure in) example:', output),
                        "Couldn't match 'Failure in example: ' "
                        "or 'Failed example: '")
        expect = [self.doubleSeparator,
                  re.compile(r'\[(ERROR|FAIL)\]')]
        self.stringComparison(expect, output.splitlines())

        A problem encountered while running a doctest is reported in the output
        stream with a I{FAIL} or I{ERROR} tag along with a summary of what
        problem was encountered and the ID of the test.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/trial/test/test_reporter.py