public void testNewTreeSetEmptyWithComparator() {
    TreeSet<Integer> set = Sets.newTreeSet(SOME_COMPARATOR);
    verifySortedSetContents(set, EMPTY_COLLECTION, SOME_COMPARATOR);
  }

  public void testNewIdentityHashSet() {
    Set<Integer> set = Sets.newIdentityHashSet();
    Integer value1 = new Integer(12357);
    Integer value2 = new Integer(12357);
    assertTrue(set.add(value1));
    assertFalse(set.contains(value2));