def METHOD_NAME(self):
    form = PageUpdateForm(
        data={
            "url": "/%* /",
            "title": "Title",
            "content": "Content",
        }
    )
    self.assertFalse(form.is_valid())
    self.assertEqual(
        form.errors["url"],
        [
            "This value must contain only letters, numbers, dots, underscores, dashes, slashes or tildes."
        ],
    )