@Override
    public boolean removeAll(Collection<?> elementsToRemove) {
        boolean setChanged = false;
        for (Object objectToRemove : elementsToRemove) {
            setChanged |= remove(objectToRemove.hashCode());
        }

        return setChanged;
    }
@Test
    public void testRemoveAll() {
        final OAHashSet<Integer> set = new OAHashSet<>(8);
        populateSet(set, 10);

        Collection<Integer> elementsToRemove = new ArrayList<>(10);
        for (int i = 0; i < 10; i++) {
            elementsToRemove.add(i);
        }

        final boolean removedAll = set.removeAll(elementsToRemove);
        assertTrue("All elements should be removed", removedAll);
        assertTrue(set.isEmpty());
    }