Keep dynamically added model receivers at the end when unmuting signals

factory/django.py

@@ -306,8 +306,13 @@ def __exit__(self, exc_type, exc_value, traceback):
             logger.debug('mute_signals: Restoring signal handlers %r',
                          receivers)
 
-            signal.receivers += receivers
             with signal.lock:
+                new_receivers = signal.receivers
+                signal.receivers = receivers
+                for lookup_key, receiver in new_receivers:
+                    # add dynamic receivers same way django signal adds them
+                    if all(r_key != lookup_key for r_key, _ in signal.receivers):
+                        signal.receivers.append((lookup_key, receiver))
                 # Django uses some caching for its signals.
                 # Since we're bypassing signal.connect and signal.disconnect,
                 # we have to keep messing with django's internals.

tests/test_django.py

@@ -927,10 +927,17 @@ def test_context_manager(self):
         self.assertSignalsReactivated()
 
     def test_receiver_created_during_model_instantiation_is_not_lost(self):
+        original_receiver_keys = [r_key for r_key, _ in signals.post_save.receivers]
+
         with factory.django.mute_signals(signals.post_save):
             instance = WithSignalsFactory(post_save_signal_receiver=self.handlers.created_during_instantiation)
             self.assertTrue(self.handlers.created_during_instantiation.called)
 
+        restored_receiver_keys = [r_key for r_key, _ in signals.post_save.receivers]
+        self.assertTrue(
+            all(orig == restored for orig, restored in zip(original_receiver_keys, restored_receiver_keys))
+        )
+
         self.handlers.created_during_instantiation.reset_mock()
         instance.save()