@Test
public void testClear() {

  LOG.info("Test clear");
  // use addAll
  set.addAll(list);
  assertEquals(NUM, set.size());
  assertFalse(set.isEmpty());
  // clear the set
  set.clear();
  assertEquals(0, set.size());
  assertTrue(set.isEmpty());
  // iterator should be empty
  Iterator<Integer> iter = set.iterator();
  assertFalse(iter.hasNext());
  LOG.info("Test clear - DONE");
}