Add tests for batch ops
Add tests for batch ops

mizchi/idb-wrapper-promisify,mizchi/idb-wrapper-promisify,rubenstolk/IDBWrapper,safetychanger/IDBWrapper,kilbot/IDBWrapper,rubenstolk/IDBWrapper,kilbot/IDBWrapper,jensarps/IDBWrapper,jensarps/IDBWrapper,jayfunk/IDBWrapper,jayfunk/IDBWrapper,safetychanger/IDBWrapper