public void test_plusDays_symmetry(OffsetDate reference) {

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

      t = reference.plusDays(-days).plusDays(days);
      assertEquals(t, reference);
    }
  }

  @Test(groups = { "tck" }