Assert that rollback is not attempted when there are no errors.

Signed-off-by: Eric Peterson <ericpeterson@spotify.com>

plugins/search-backend-module-pg/src/PgSearchEngine/PgSearchEngineIndexer.test.ts

@@ -65,6 +65,7 @@ describe('PgSearchEngineIndexer', () => {
     );
     expect(database.completeInsert).toHaveBeenCalledWith(tx, 'my-type');
     expect(tx.commit).toHaveBeenCalled();
+    expect(tx.rollback).not.toHaveBeenCalled();
   });
 
   it('should batch insert documents', async () => {