@Test
  public void fliptest2() {
    final MutableRoaringBitmap rb = new MutableRoaringBitmap();
    rb.add(0);
    rb.add(2);
    final MutableRoaringBitmap rb2 = ImmutableRoaringBitmap.flip(rb, 0, 3);
    final MutableRoaringBitmap result = new MutableRoaringBitmap();
    result.add(1);

    Assert.assertEquals(result, rb2);
  }