fix: fix WorkItem migration

This commit fixes the migrations that adds `name` and `description` to
the `WorkItem` model. Historical lookups of `id` must always use
`filter`.

caluma/caluma_workflow/migrations/0022_workitem_name_description.py

@@ -13,12 +13,12 @@ def set_name_and_description(apps, schema_editor):
         work_item.name = work_item.task.name
         work_item.description = work_item.task.description
         work_item.save()
-        historical_work_item = HistoricalWorkItem.objects.using(db_alias).get(
+        for historical_work_item in HistoricalWorkItem.objects.using(db_alias).filter(
             id=work_item.pk
-        )
-        historical_work_item.name = work_item.name
-        historical_work_item.description = work_item.description
-        historical_work_item.save()
+        ):
+            historical_work_item.name = work_item.name
+            historical_work_item.description = work_item.description
+            historical_work_item.save()
 
 
 class Migration(migrations.Migration):

caluma/caluma_workflow/tests/test_migrations.py

@@ -94,7 +94,7 @@ def test_workitem_name_description(transactional_db):
     task = Task.objects.create(name="task_name", description="task_description")
     work_item = WorkItem.objects.create(child_case=None, case=case, task=task)
 
-    historical_work_item = HistoricalWorkItem.objects.create(
+    HistoricalWorkItem.objects.create(
         id=work_item.pk,
         child_case=None,
         case=case,
@@ -104,6 +104,16 @@ def test_workitem_name_description(transactional_db):
         history_date=timezone.now(),
     )
 
+    HistoricalWorkItem.objects.create(
+        id=work_item.pk,
+        child_case=None,
+        case=case,
+        task=task,
+        created_at=timezone.now() + timezone.timedelta(hours=1),
+        modified_at=timezone.now() + timezone.timedelta(hours=1),
+        history_date=timezone.now() + timezone.timedelta(hours=1),
+    )
+
     # Migrate forwards.
     executor.loader.build_graph()  # reload.
     executor.migrate(migrate_to)
@@ -115,8 +125,8 @@ def test_workitem_name_description(transactional_db):
 
     # Refresh objects
     work_item = WorkItem.objects.get(pk=work_item.pk)
-    historical_work_item = HistoricalWorkItem.objects.get(pk=historical_work_item.pk)
+    historical_work_items = HistoricalWorkItem.objects.filter(id=work_item.pk)
 
-    for wi in [work_item, historical_work_item]:
+    for wi in [work_item, *historical_work_items]:
         assert wi.name == wi.task.name
         assert wi.description == wi.task.description