def test_renderHEAD(self):
        """
        The rendering behavior of L{UnauthorizedResource} for a I{HEAD} request
        is like its handling of a I{GET} request, but no response body is
        written.
        """
        request = self.makeRequest(method=b'HEAD')
        self._unauthorizedRenderTest(request)
        self.assertEqual(b'', b''.join(request.written))

        The rendering behavior of L{UnauthorizedResource} for a I{HEAD} request
        is like its handling of a I{GET} request, but no response body is
        written.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/web/test/test_httpauth.py