Minutes ago helper function for Calendar objects

CalendarUtils.java

public static long minutesAgo(Calendar before, Calendar after){
  long diff = after.getTimeInMillis() - before.getTimeInMillis();
  return TimeUnit.MILLISECONDS.toMinutes(diff);
}

// junit test for the method above
@Test
public void testThreeMinutesAgo() throws Exception {
  Calendar now = Calendar.getInstance();
  Calendar threeMinutesAgo = (Calendar) now.clone();
  threeMinutesAgo.add(Calendar.MINUTE, -3);

  assertEquals("3 minutes ago", minutesAgo(threeMinutesAgo, now)+ " minutes ago");
}