@Override
    public void clear() {
        items.clear();
    }
@Test
    public void testClear() throws Exception {
        //Test set emptying
        assertTrue("The set should be initialized empty.", set.isEmpty());
        set.clear();
        assertTrue("Clear should have no effect on an empty set.", set.isEmpty());
        fillSet(10, set);
        assertFalse("The set should no longer be empty.", set.isEmpty());
        set.clear();
        assertTrue("The set should be empty after clear.", set.isEmpty());
    }