Hashing.hmacSha1(SHA1_KEY)
            .newHasher()
            .putString("hello", UTF_8)
            .putString("world", UTF_8)
            .hash());
  }

  public void testMultipleUpdatesDoFinal() throws Exception {
    Mac mac = Mac.getInstance("HmacSHA1");
    mac.init(SHA1_KEY);
    mac.update("hello".getBytes(UTF_8));
    mac.update("world".getBytes(UTF_8));

    assertEquals(