return integers().minValue();
        }

        @Override
        public Integer maxValue() {
          return integers().maxValue();
        }
      };

  public void testInvalidIntRange() {
    assertThrows(IllegalArgumentException.class, () -> ContiguousSet.closed(2, 1));
    assertThrows(IllegalArgumentException.class, () -> ContiguousSet.closedOpen(2, 1));
  }

  public void testInvalidLongRange() {