def METHOD_NAME(self):
    """readonly field can't be edited via api"""
    test_link = reverse("misago:api:user-edit-details", kwargs={"pk": self.user.pk})
    response = self.client.post(test_link, data={"join_ip": "88.12.13.14"})
    self.assertEqual(response.status_code, 200)
    self.reload_user()
    self.assertNotIn("join_ip", self.user.profile_fields)