def _runFixturesAndTest(self, result):
        """
        Really run C{setUp}, the test method, and C{tearDown}.  Any of these may
        return L{defer.Deferred}s. After they complete, do some reactor cleanup.

        @param result: A L{TestResult} object.
        """
        from twisted.internet import reactor
        self._deprecateReactor(reactor)
        self._timedOut = False
        try:
            d = self.deferSetUp(None, result)
            try:
                self._wait(d)
            finally:
                self._cleanUp(result)
                self._classCleanUp(result)
        finally:
            self._undeprecateReactor(reactor)

        Really run C{setUp}, the test method, and C{tearDown}.  Any of these may
        return L{defer.Deferred}s. After they complete, do some reactor cleanup.

        @param result: A L{TestResult} object.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/trial/_asynctest.py