@Test
public void testSumSince() {

    DecimalType sum = PersistenceExtensions.sumSince(item,
            ZonedDateTime.of(1940, 1, 1, 0, 0, 0, 0, ZoneId.systemDefault()), TestPersistenceService.ID);
    assertNotNull(sum);
    assertEquals(0.0, sum.doubleValue(), 0.001);
    sum = PersistenceExtensions.sumSince(item, ZonedDateTime.of(2005, 1, 1, 0, 0, 0, 0, ZoneId.systemDefault()),
            TestPersistenceService.ID);
    assertNotNull(sum);
    assertEquals(IntStream.of(2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012).sum(), sum.doubleValue(), 0.001);
    // default persistence service
    sum = PersistenceExtensions.sumSince(item, ZonedDateTime.of(2005, 1, 1, 0, 0, 0, 0, ZoneId.systemDefault()));
    assertNotNull(sum);
    assertEquals(0.0, sum.doubleValue(), 0.001);
}