fix failing tests

Author: ciur

papermerge/core/features/custom_fields/db/api.py

@@ -203,9 +203,13 @@ def update_custom_field(
     if attrs.group_id:
         cfield.user_id = None
         cfield.group_id = attrs.group_id
-    else:
+    elif attrs.user_id:
         cfield.user_id = attrs.user_id
         cfield.group_id = None
+    else:
+        raise ValueError(
+            "Either attrs.user_id or attrs.group_id should be non-empty value"
+        )
 
     session.commit()
     result = schema.CustomField.model_validate(cfield)

papermerge/core/features/custom_fields/tests/test_dbapi_custom_fields.py

@@ -45,7 +45,7 @@ def test_custom_field_update(db_session: Session, user: User):
     dbapi.update_custom_field(
         db_session,
         custom_field_id=cfield.id,
-        attrs=schema.UpdateCustomField(name="new_cf1_name"),
+        attrs=schema.UpdateCustomField(name="new_cf1_name", user_id=user.id),
     )
 
     updated_cf1 = dbapi.get_custom_field(db_session, cfield.id)