Remove assertContains from private thread start api tests

misago/threads/tests/test_privatethread_start_api.py

@@ -35,14 +35,20 @@ class StartPrivateThreadTests(AuthenticatedUserTestCase):
         override_acl(self.user, {'can_use_private_threads': 0})
 
         response = self.client.post(self.api_link)
-        self.assertContains(response, "You can't use private threads.", status_code=403)
+        self.assertEqual(response.status_code, 403)
+        self.assertEqual(response.json(), {
+            "detail": "You can't use private threads.",
+        })
 
     def test_cant_start_private_thread(self):
         """permission to start private thread is validated"""
         override_acl(self.user, {'can_start_private_threads': 0})
 
         response = self.client.post(self.api_link)
-        self.assertContains(response, "You can't start private threads.", status_code=403)
+        self.assertEqual(response.status_code, 403)
+        self.assertEqual(response.json(), {
+            "detail": "You can't start private threads.",
+        })
 
     def test_empty_data(self):
         """no data sent handling has no showstoppers"""