@Override
  public StoreInfo get(List<? extends StoreKey> ids, EnumSet<StoreGetOptions> getOptions) throws StoreException {
    // unused function
    List<MessageInfo> infos = new ArrayList<>();
    List<ByteBuffer> buffers = new ArrayList<>();
    List<StoreKey> keys = new ArrayList<>();
    for (StoreKey id : ids) {
      for (int i = 0; i < messageInfos.size(); i++) {
        MessageInfo info = messageInfos.get(i);
        if (info.getStoreKey().equals(id)) {
          infos.add(info);
          buffers.add(log.getData(i));
          keys.add(info.getStoreKey());
        }
      }
    }
    return new StoreInfo(new MockMessageReadSet(buffers, keys), infos);
  }
Log that stores all data in memory.
ambry-replication/src/test/java/com/github/ambry/replication/InMemoryStore.java