@Test
  public void concurrentTtlUpdateTest() throws Exception {
    int extraBlobCount = 2000 / PUT_RECORD_SIZE + 1;
    List<MockId> ids = put(extraBlobCount, PUT_RECORD_SIZE, expiresAtMs);
    List<TtlUpdater> ttlUpdaters = new ArrayList<>();
    for (MockId id : ids) {
      ttlUpdaters.add(new TtlUpdater(id));
    }
    ExecutorService executorService = Executors.newFixedThreadPool(ttlUpdaters.size());
    try {
      List<Future<CallableResult>> futures = executorService.invokeAll(ttlUpdaters);
      verifyTtlUpdateFutures(ttlUpdaters, futures);
    } finally {
      executorService.shutdownNow();
    }
  }
Tests the case where there are many concurrent ttl updates.
@throws Exception
ambry-store/src/test/java/com/github/ambry/store/BlobStoreTest.java