public void testToDateTimeToday_nullZone() {
    LocalTime base = new LocalTime(10, 20, 30, 40, COPTIC_PARIS); // PARIS irrelevant
    DateTime dt = new DateTime(2004, 6, 9, 6, 7, 8, 9);
    DateTimeUtils.setCurrentMillisFixed(dt.getMillis());

    DateTime test = base.toDateTimeToday((DateTimeZone) null);
    check(base, 10, 20, 30, 40);
    DateTime expected = new DateTime(dt.getMillis(), COPTIC_LONDON);
    expected = expected.hourOfDay().setCopy(10);
    expected = expected.minuteOfHour().setCopy(20);
    expected = expected.secondOfMinute().setCopy(30);
    expected = expected.millisOfSecond().setCopy(40);
    assertEquals(expected, test);
  }