public void getHoursReturnTheSumOfAllHours() {
HoursGroup h1 = createHoursGroupWithCriterions(criterion1, criterion2);
h1.setWorkingHours(10);
HoursGroup h2 = createHoursGroupWithCriterions(criterion1, criterion2);
h2.setWorkingHours(5);
AggregatedHoursGroup aggregate = AggregatedHoursGroup.aggregate(h1, h2)
.get(0);
assertThat(aggregate.getHours(), equalTo(15));
}