@Test(groups = "unittest")
  public void testNotFound2() {
    Set<String> first = new HashSet<String>(Arrays.asList("one", "two", "twohalf", "three"));
    Set<String> second = new HashSet<String>(Arrays.asList("one", "two", "twohalf", "three"));

    Set<String> notFound = (Set<String>) CollectionUtils.firstNotFoundInSecond(first, second);

    Assert.assertTrue(notFound.size() == 0);
  }
  @Test(groups = "unittest")
  public void testNotFound() {
    Set<String> first = new HashSet<String>(Arrays.asList("one", "two", "twohalf", "three"));
    Set<String> second = new HashSet<String>(Arrays.asList("two", "three", "four"));

    Set<String> notFound = (Set<String>) CollectionUtils.firstNotFoundInSecond(first, second);

    for (String string : notFound)
      Assert.assertTrue(string.equals("one") || string.equals("twohalf"));
  }
  @Test(groups = "unittest")
  public void testNotFoundBlock() {
    UUID uuid0 = UUID.randomUUID();
    UUID uuid1 = UUID.randomUUID();
    UUID uuid2 = UUID.randomUUID();
    UUID uuid3 = UUID.randomUUID();
    UUID uuid4 = UUID.randomUUID();

    Set<Block> first =
        new HashSet<Block>(Arrays.asList(getBlock(uuid0), getBlock(uuid1), getBlock(uuid2)));
    Set<Block> second =
        new HashSet<Block>(Arrays.asList(getBlock(uuid2), getBlock(uuid3), getBlock(uuid4)));

    Set<Block> notFound = (Set<Block>) CollectionUtils.firstNotFoundInSecond(first, second);

    for (Block block : notFound)
      Assert.assertTrue(block.getId().equals(uuid1) || block.getId().equals(uuid0));
  }