def test_wsgi(self):
        """
        The I{--wsgi} option takes the fully-qualifed Python name of a WSGI
        application object and creates a L{WSGIResource} at the root which
        serves that application.
        """
        options = Options()
        options.parseOptions(['--wsgi', __name__ + '.application'])
        root = options['root']
        self.assertTrue(root, WSGIResource)
        self.assertIdentical(root._reactor, reactor)
        self.assertTrue(isinstance(root._threadpool, ThreadPool))
        self.assertIdentical(root._application, application)

        # The threadpool should start and stop with the reactor.
        self.assertFalse(root._threadpool.started)
        reactor.fireSystemEvent('startup')
        self.assertTrue(root._threadpool.started)
        self.assertFalse(root._threadpool.joined)
        reactor.fireSystemEvent('shutdown')
        self.assertTrue(root._threadpool.joined)

        The I{--wsgi} option takes the fully-qualifed Python name of a WSGI
        application object and creates a L{WSGIResource} at the root which
        serves that application.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/web/test/test_tap.py