public MockId addRandomBlobToStore(Store store, long size, long expiresAtMs) throws StoreException {
    final Random random = new Random();
    short accountId = Utils.getRandomShort(TestUtils.RANDOM);
    short containerId = Utils.getRandomShort(TestUtils.RANDOM);
    short lifeVersion = MessageInfo.LIFE_VERSION_FROM_FRONTEND;

    MockId id = new MockId(TestUtils.getRandomString(MOCK_ID_STRING_LENGTH), accountId, containerId);
    long crc = random.nextLong();
    MessageInfo info =
        new MessageInfo(id, size, false, false, false, expiresAtMs, crc, id.getAccountId(), id.getContainerId(),
            Utils.Infinite_Time, lifeVersion);
    ByteBuffer buffer = ByteBuffer.wrap(TestUtils.getRandomBytes((int) size));
    store.put(new MockMessageWriteSet(Collections.singletonList(info), Collections.singletonList(buffer)));
    return id;
  }
Helper util to add blobs to a given Store
@param store store to add blob to.
@param size size in bytes of the randomized blob
@param expiresAtMs expiry in milliseconds to be set for the blob
@return {@link MockId} the mock id of the blob added
@throws StoreException
ambry-store/src/test/java/com/github/ambry/store/StorageManagerTest.java