'sign/unsign should be reversible'

def test_sign_unsign(self):

    signer = signing.Signer('predictable-secret')
    examples = ['q;wjmbk;wkmb', '3098247529087', '3098247:529:087:', 'jkw    osanteuh    ,rcuh    nthu    aou    oauh    ,ud    du', '\\u2019']
    for example in examples:
        signed = signer.sign(example)
        self.assertIsInstance(signed, str)
        self.assertNotEqual(example, signed)
        self.assertEqual(example, signer.unsign(signed))
