Fixed #30457 -- Added TestCase.captureOnCommitCallbacks().

django/test/testcases.py

@@ -1229,6 +1229,21 @@ class TestCase(TransactionTestCase):
             not connection.needs_rollback and connection.is_usable()
         )
 
+    @classmethod
+    @contextmanager
+    def captureOnCommitCallbacks(cls, *, using=DEFAULT_DB_ALIAS, execute=False):
+        """Context manager to capture transaction.on_commit() callbacks."""
+        callbacks = []
+        start_count = len(connections[using].run_on_commit)
+        try:
+            yield callbacks
+        finally:
+            run_on_commit = connections[using].run_on_commit[start_count:]
+            callbacks[:] = [func for sids, func in run_on_commit]
+            if execute:
+                for callback in callbacks:
+                    callback()
+
 
 class CheckCondition:
     """Descriptor class for deferred condition checking."""