d = createTestDate(1492, 4, 21, 23, 56, 31, 555);
d.truncate(TimeUnit.HOUR);
assertEquals(1492, 4, 21, 23, 0, 0, d);
d = createTestDate(1492, 4, 21, 23, 56, 31, 555);
d.truncate(TimeUnit.MIN);
assertEquals(1492, 4, 21, 23, 56, 0, d);
d = createTestDate(1492, 4, 21, 23, 56, 31, 555);
d.truncate(TimeUnit.SEC);
assertEquals(1492, 4, 21, 23, 56, 31, d);