def test_renderWithoutHost(self):
        """
        L{NameVirtualHost.render} returns the result of rendering the
        instance's C{default} if it is not L{None} and there is no I{Host}
        header in the request.
        """
        virtualHostResource = NameVirtualHost()
        virtualHostResource.default = Data(b"correct result", "")
        request = DummyRequest([''])
        self.assertEqual(
            virtualHostResource.render(request), b"correct result")

        L{NameVirtualHost.render} returns the result of rendering the
        instance's C{default} if it is not L{None} and there is no I{Host}
        header in the request.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/web/test/test_vhost.py