Ensure IDBDatabase wrapper isn't prematurely collected. On success, you will see a series of "PASS" messages, followed by "TEST COMPLETE". indexedDB.deleteDatabase(dbname) openDB(): indexedDB.open(dbname, 1) onUpgradeNeeded(): db = event.target.result db.createObjectStore('store').createIndex('index', 'keyPath') db = null openSuccess(): sawVersionChangeEvent = false collectGarbage(): self.gc() openAgain(): indexedDB.open(dbname, 2) onVersionChange(): event.target.close() sawVersionChangeEvent = true openAgainSuccess(): PASS sawVersionChangeEvent is true PASS successfullyParsed is true TEST COMPLETE