@Test
public void testRemoveAll() {

  LOG.info("Test remove all");
  for (Integer i : list) {
    assertTrue(set.add(i));
  }
  for (int i = 0; i < NUM; i++) {
    assertTrue(set.remove(list.get(i)));
  }
  // the deleted elements should not be there
  for (int i = 0; i < NUM; i++) {
    assertFalse(set.contains(list.get(i)));
  }
  // iterator should not have next
  Iterator<Integer> iter = set.iterator();
  assertFalse(iter.hasNext());
  assertTrue(set.isEmpty());
  LOG.info("Test remove all - DONE");
}