}

        @Override
        public long distance(Integer start, Integer end) {
          return integers().distance(start, end);
        }
      };

  public void testCanonical() {
    assertEquals(Range.closedOpen(1, 5), Range.closed(1, 4).canonical(integers()));
    assertEquals(Range.closedOpen(1, 5), Range.open(0, 5).canonical(integers()));