def test_hiddenException(self):
        """
        Check that errors in C{DelayedCall}s get reported, even if the
        test already has a failure.

        Only really necessary for testing the deprecated style of tests that
        use iterate() directly. See
        L{erroneous.DelayedCall.testHiddenException} for more details.
        """
        from twisted.internet import reactor
        if reflect.qual(reactor).startswith("twisted.internet.asyncioreactor"):
            raise self.skipTest(
                ("This test does not work on the asyncio reactor, as the "
                 "traceback comes from inside asyncio, not Twisted."))

        test = erroneous.DelayedCall('testHiddenException')
        output = self.getOutput(test).splitlines()
        errorQual = qual(RuntimeError)
        match = [
            self.doubleSeparator,
            '[FAIL]',
            'Traceback (most recent call last):',
            re.compile(r'^\s+File .*erroneous\.py., line \d+, in '
                       'testHiddenException$'),
            re.compile(r'^\s+self\.fail\("Deliberate failure to mask the '
                       'hidden exception"\)$'),
            'twisted.trial.unittest.FailTest: '
            'Deliberate failure to mask the hidden exception',
            'twisted.trial.test.erroneous.DelayedCall.testHiddenException',
            self.doubleSeparator,
            '[ERROR]',
            'Traceback (most recent call last):',
            re.compile(r'^\s+File .* in runUntilCurrent'),
            re.compile(r'^\s+.*'),
            re.compile('^\s+File .*erroneous\.py", line \d+, in go'),
            re.compile('^\s+raise RuntimeError\(self.hiddenExceptionMsg\)'),
            errorQual + ': something blew up',
            'twisted.trial.test.erroneous.DelayedCall.testHiddenException']
        self.stringComparison(match, output)

        Check that errors in C{DelayedCall}s get reported, even if the
        test already has a failure.

        Only really necessary for testing the deprecated style of tests that
        use iterate() directly. See
        L{erroneous.DelayedCall.testHiddenException} for more details.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/trial/test/test_reporter.py