public void test_plusWeeks_symmetry(OffsetDate reference) {

    for (int weeks = 0; weeks < 365 * 8; weeks++) {
      OffsetDate t = reference.plusWeeks(weeks).plusWeeks(-weeks);
      assertEquals(t, reference);

      t = reference.plusWeeks(-weeks).plusWeeks(weeks);
      assertEquals(t, reference);
    }
  }

  @Test(groups = { "tck" }