### Question:
Logging { public static String duration(long start, long end) { long duration = end - start; long millis = duration % 1000; long secs = duration / 1000; long mins = secs / 60; secs = secs % 60; return String.format("%d minutes %d seconds %d millis", mins, secs, millis); }  static String duration(long start, long end);  }### Answer:
@Test public void testDuration() { assertEquals("0 minutes 0 seconds 0 millis", Logging.duration(10, 10)); assertEquals("0 minutes 0 seconds 155 millis", Logging.duration(100000, 100155)); assertEquals("3 minutes 15 seconds 395 millis", Logging.duration(555555555, 555750950)); assertEquals("200 minutes 15 seconds 395 millis", Logging.duration(555555555, 567570950)); }