assertEquals(range, rangeMap.span());
        assertFalse(range.isEmpty());
      } catch (NoSuchElementException e) {
        assertTrue(range.isEmpty());
      }
    }
  }

  public void testSpanTwoRanges() {
    for (Range<Integer> range1 : RANGES) {
      for (Range<Integer> range2 : RANGES) {
        RangeMap<Integer, Integer> rangeMap = TreeRangeMap.create();
        rangeMap.put(range1, 1);