@Override
    public void clearIgnoringIndexes() {
        size = 0;
    }
@Test
    public void testClearIgnoringIndexes() {
        PriorityQueue<TestElement> queue = new DefaultPriorityQueue<TestElement>(TestElementComparator.INSTANCE, 0);
        assertEmptyQueue(queue);

        TestElement a = new TestElement(5);
        TestElement b = new TestElement(10);
        TestElement c = new TestElement(2);
        TestElement d = new TestElement(6);
        TestElement e = new TestElement(11);

        assertOffer(queue, a);
        assertOffer(queue, b);
        assertOffer(queue, c);
        assertOffer(queue, d);

        queue.clearIgnoringIndexes();
        assertEmptyQueue(queue);

        // Elements cannot be re-inserted but new ones can.
        try {
            queue.offer(a);
            fail();
        } catch (IllegalArgumentException t) {
            // expected
        }

        assertOffer(queue, e);
        assertSame(e, queue.peek());
    }