// -----------------------------------------------------------------------
 public void testGetMillis() {
   MutableInterval test = new MutableInterval(TEST_TIME1, TEST_TIME2);
   assertEquals(TEST_TIME1, test.getStartMillis());
   assertEquals(TEST_TIME1, test.getStart().getMillis());
   assertEquals(TEST_TIME2, test.getEndMillis());
   assertEquals(TEST_TIME2, test.getEnd().getMillis());
   assertEquals(TEST_TIME2 - TEST_TIME1, test.toDurationMillis());
   assertEquals(TEST_TIME2 - TEST_TIME1, test.toDuration().getMillis());
 }
 public void testGetDuration2() {
   MutableInterval test = new MutableInterval(TEST_TIME1, TEST_TIME1);
   assertSame(Duration.ZERO, test.toDuration());
 }