### Question:
DateUtil { public static synchronized String isoDateFromMillis(long millis) { return getDateFormat().format(new Date(millis)); } private  DateUtil(); static synchronized String isoDateFromMillis(long millis); static DateFormat createLocaleIndependentDateFormatter(String dateFormatString); static Date getCorrectedDate();  }### Answer:
@Test public void isoDateFromEpoch0() { assertThat(isoDateFromMillis(0), is("1970-01-01T00:00:00.000Z")); }
@Test public void isoDateFromKnownTimeStamp() { assertThat(isoDateFromMillis(1370114707266l), is("2013-06-01T19:25:07.266Z")); assertThat(isoDateFromMillis(1370114707266l + 1l), is("2013-06-01T19:25:07.267Z")); }
@Test public void isoDateFromKnownTimeStampRoundedToSec() { assertThat(isoDateFromMillis(1370114707000l), is("2013-06-01T19:25:07.000Z")); }