private short undelete(MockId idToUndelete) throws StoreException {
    MessageInfo putMsgInfo = allKeys.get(idToUndelete).getFirst();
    MessageInfo info =
        new MessageInfo(idToUndelete, UNDELETE_RECORD_SIZE, putMsgInfo.getAccountId(), putMsgInfo.getContainerId(),
            time.milliseconds(), MessageInfo.LIFE_VERSION_FROM_FRONTEND);
    short lifeVersion = store.undelete(info);
    deletedKeys.remove(idToUndelete);
    liveKeys.add(idToUndelete);
    undeletedKeys.add(idToUndelete);
    return lifeVersion;
  }
Undeletes a blob.
@param idToUndelete the blob id to undelete.
@return the lifeVersion after undelete.
@throws StoreException
ambry-store/src/test/java/com/github/ambry/store/BlobStoreTest.java