def test_smuggle_url(self):
        data = {"ö": "ö", "abc": [3]}
        url = 'https://foo.bar/baz?x=y#a'
        smug_url = smuggle_url(url, data)
        unsmug_url, unsmug_data = unsmuggle_url(smug_url)
        self.assertEqual(url, unsmug_url)
        self.assertEqual(data, unsmug_data)

        res_url, res_data = unsmuggle_url(url)
        self.assertEqual(res_url, url)
        self.assertEqual(res_data, None)

    def test_smuggle_url(self):
        data = {"ö": "ö", "abc": [3]}
        url = "https://foo.bar/baz?x=y#a"
        smug_url = smuggle_url(url, data)
        unsmug_url, unsmug_data = unsmuggle_url(smug_url)
        self.assertEqual(url, unsmug_url)
        self.assertEqual(data, unsmug_data)

        res_url, res_data = unsmuggle_url(url)
        self.assertEqual(res_url, url)
        self.assertEqual(res_data, None)

        smug_url = smuggle_url(url, {"a": "b"})
        smug_smug_url = smuggle_url(smug_url, {"c": "d"})
        res_url, res_data = unsmuggle_url(smug_smug_url)
        self.assertEqual(res_url, url)
        self.assertEqual(res_data, {"a": "b", "c": "d"})