public void test_toString_formatter() {

    DateTimeFormatter f = DateTimeFormatters.pattern("y M d");
    String t = OffsetDate.of(2010, 12, 3, OFFSET_PONE).toString(f);
    assertEquals(t, "2010 12 3");
  }

  @Test(expectedExceptions = NullPointerException.class, groups = { "tck" }