@Override
   public boolean add(Integer integer) {
      throw new UnsupportedOperationException("RangeSet is immutable");
   }
@Test
   public void equals1() throws Exception {
      IntSet intSet = new RangeSet(4);

      SmallIntSet sis = new SmallIntSet();
      sis.add(0);
      sis.add(1);
      sis.add(2);

      // Verify equals both ways
      assertNotEquals(sis, intSet);
      assertNotEquals(intSet, sis);

      sis.add(3);

      assertEquals(sis, intSet);
      assertEquals(intSet, sis);
   }