### Question:
DateHelper { public static String getTimeString(long time) { return formatDuration(0, time, true); }  static boolean containsDate(String searchString); static String getCurrentDatetime(String format); static String getDatetime(long timestamp); static String getDatetime(String format, long timestamp); static long getTimeOfDay(Date date, int resolution); static long getTimeOfDay(long timestamp, int resolution); static String getCurrentDatetime(); static int monthNameToNumber(String monthName); static String formatDuration(long startTime); static String formatDuration(long startTime, long stopTime); static String formatDuration(long startTime, long stopTime, boolean compact); static long getIntervalLength(Date intervalStartTime, Date intervalStopTime); static String getTimeString(long time); static Date validateYear(Date date); static long getMillisecondsToNextDay(); static void main(String[] t);  }### Answer:
@Test public void testGetTimeString() { assertEquals("0ms", DateHelper.getTimeString(0)); assertEquals("3d:4h:3m:43s:872ms", DateHelper.getTimeString(273823872)); assertEquals("1m:0s:0ms", DateHelper.getTimeString(60000)); assertEquals("1h:0m:0s:0ms", DateHelper.getTimeString(3600000)); }