@Override
    public boolean containsAll(Collection<?> c) {
        checkNotNull(c, "Collection cannot be internal.");
        for (Object item : c) {
            if (!items.contains(serializer.encode(item))) {
                return false;
            }
        }
        return true;
    }
@Test
    public void testContainsAll() throws Exception {
        //Test contains with short circuiting
        Set<Integer> integersToCheck = Sets.newHashSet();
        fillSet(10, integersToCheck);
        fillSet(10, set);
        assertTrue("The sets should be identical so mutual subsets.", set.containsAll(integersToCheck));
        set.remove(9);
        assertFalse("The set should contain one fewer value.", set.containsAll(integersToCheck));
    }