assertThat(rangeSet.complement().asRanges())
        .containsExactly(Range.lessThan(1), Range.atLeast(6))
        .inOrder();
  }

  public void testFillHoleWithOverlap() {
    TreeRangeSet<Integer> rangeSet = TreeRangeSet.create();
    rangeSet.add(Range.closedOpen(1, 3));
    rangeSet.add(Range.closedOpen(4, 6));
    rangeSet.add(Range.closedOpen(2, 5));