assertFalse(range.contains(4));
    assertTrue(range.contains(5));
    assertTrue(range.contains(7));
    assertFalse(range.contains(8));
  }

  public void testSingleton() {
    Range<Integer> range = Range.closed(4, 4);
    assertFalse(range.contains(3));
    assertTrue(range.contains(4));
    assertFalse(range.contains(5));
    assertTrue(range.hasLowerBound());