test: verify that bulk event is not emitted on transaction rollback

Author: bradenmacdonald

src/openedx_content/applets/publishing/signals.py

@@ -73,6 +73,11 @@ class DraftChangeLogEventData:
 """
 The draft version of one or more entities in a `LearningPackage` has changed.
 
+This is emitted for when the first version of an entity is created, when a new
+version of an entity is created (i.e. the entity is modified), when an entity is
+reverted to an old version, or when an entity is deleted. (All referring to the
+draft version of the entity.)
+
 This is a low-level batch event. It does not have any course or library context
 information available. It does not distinguish between Containers, Components,
 or other entity types.

tests/openedx_content/applets/publishing/test_signals.py

@@ -3,12 +3,12 @@
 """
 
 from datetime import datetime, timezone
+from typing import Any
 
 import pytest
-from django.db import transaction
 
 from openedx_content import api
-from tests.utils import capture_events
+from tests.utils import abort_transaction, capture_events
 
 pytestmark = pytest.mark.django_db(transaction=True)
 now_time = datetime.now(tz=timezone.utc)
@@ -64,14 +64,10 @@ def test_single_entity_changed_abort() -> None:
     entity = api.create_publishable_entity(learning_package.id, key="entity1", created=now_time, created_by=None)
 
     with capture_events(expected_count=0):
-        try:
-            with transaction.atomic():
-                api.create_publishable_entity_version(
-                    entity.id, version_num=1, title="Entity 1 V1", created=now_time, created_by=None
-                )
-                raise DeliberateRollbackException()
-        except DeliberateRollbackException:
-            pass
+        with abort_transaction():
+            api.create_publishable_entity_version(
+                entity.id, version_num=1, title="Entity 1 V1", created=now_time, created_by=None
+            )
 
 
 def test_multiple_entites_changed(admin_user) -> None:
@@ -121,3 +117,33 @@ def test_multiple_entites_changed(admin_user) -> None:
         api.signals.ChangeLogRecordData(entity_id=entity3.id, old_version=1, new_version=None),
     ]
     assert event.kwargs["metadata"].time == now_time
+
+
+def test_multiple_entites_change_aborted() -> None:
+    """
+    Test that LEARNING_PACKAGE_ENTITIES_CHANGED is NOT emitted when we roll back
+    a transaction that would have modified multiple entities in a bulk change.
+    """
+    learning_package = api.create_learning_package(key="lp1", title="Test LP 📦")
+    created_args: dict[str, Any] = {"created": now_time, "created_by": None}
+
+    # Entity 1 will have no initial version:
+    entity1 = api.create_publishable_entity(learning_package.id, key="entity1", **created_args)
+    # Entity 2 will have an initial version:
+    entity2 = api.create_publishable_entity(learning_package.id, key="entity2", **created_args)
+    api.create_publishable_entity_version(entity2.id, version_num=1, title="Entity 2 V1", **created_args)
+    # Entity 3 will have an initial version that later gets deleted:
+    entity3 = api.create_publishable_entity(learning_package.id, key="entity3", **created_args)
+    api.create_publishable_entity_version(entity3.id, version_num=1, title="Entity 3 V1", **created_args)
+
+    with capture_events(expected_count=0):
+        with abort_transaction():
+            with api.bulk_draft_changes_for(learning_package.id, changed_by=None, changed_at=now_time):
+                # Note: the 'created_args' values below get ignored because of the bulk context.
+                # Create two versions of entity1:
+                api.create_publishable_entity_version(entity1.id, version_num=1, title="Entity 1 V1", **created_args)
+                api.create_publishable_entity_version(entity1.id, version_num=2, title="Entity 1 V2", **created_args)
+                # Create a version 2 of entity 2:
+                api.create_publishable_entity_version(entity2.id, version_num=2, title="Entity 2 V2", **created_args)
+                # Delete entity 3:
+                api.set_draft_version(entity3.id, None, set_at=now_time, set_by=None)

tests/utils.py

@@ -8,6 +8,7 @@
 from dataclasses import dataclass
 from typing import Generator
 
+from django.db import transaction
 from openedx_events.tooling import OpenEdxPublicSignal  # type: ignore[import-untyped]
 
 
@@ -77,3 +78,27 @@ def receiver(sender, **kwargs):  # pylint: disable=unused-argument
         assert len(captured) == expected_count, (
             f"Expected {expected_count} event(s), got {len(captured)}: {[e.signal for e in captured]}"
         )
+
+
+class DeliberateRollbackException(Exception):
+    """Exception used to deliberately cancel and roll back a DB transaction"""
+
+
+@contextmanager
+def abort_transaction() -> Generator[None, None, None]:
+    """
+    Context manager that wraps the block in a transaction that gets rolled back.
+
+    Example usage::
+
+        with abort_transaction():
+            api.do_something(...)
+
+        assert nothing was done
+    """
+    try:
+        with transaction.atomic():
+            yield
+            raise DeliberateRollbackException
+    except DeliberateRollbackException:
+        pass