@Test
public void testRemaining() {

    final int oneHourInMillis = 60_000 * 60;
    final long nowPlusOneHour = System.currentTimeMillis() + oneHourInMillis;
    final Deadline deadline = Deadline.fromUnixMilliseconds(nowPlusOneHour);
    Assert.assertEquals(nowPlusOneHour, deadline.getValue());
    Assert.assertTrue(deadline.remaining() > 0);
    Assert.assertTrue(deadline.remaining() <= oneHourInMillis);
}