@VisibleForTesting
    Date calcMostRecentDateForDeletion(@NonNull Date currentDate) {
        return minusHours(currentDate, numberOfHoursAfterPlayback);
    }
@Test
    public void testCalcMostRecentDateForDeletion() throws Exception {
        APCleanupAlgorithm algo = new APCleanupAlgorithm(24);
        Date curDateForTest = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ssZ").parse("2018-11-13T14:08:56-0800");
        Date resExpected = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ssZ").parse("2018-11-12T14:08:56-0800");
        Date resActual = algo.calcMostRecentDateForDeletion(curDateForTest);
        assertEquals("cutoff for retaining most recent 1 day", resExpected, resActual);
    }