assertThat(rangeSet.asRanges()).containsExactly(a, b).inOrder();
      } else {
        assertThat(rangeSet.asRanges()).containsExactly(b, a).inOrder();
      }
    }
  }

  public void testRemoveEmpty() {
    TreeRangeSet<Integer> rangeSet = TreeRangeSet.create();
    rangeSet.add(Range.closed(1, 6));
    rangeSet.remove(Range.closedOpen(3, 3));
    testInvariants(rangeSet);