@Test
public void testBuilderByDate() {

    CustomFactory<Date> factory = new CustomFactory<Date>() {
        @Override
        public Builder2<Date> builderOf(ObsGathering gathering) {
            return builderByDate(new GregorianCalendar(), gathering);
        }
        @Override
        public Date dateOf(int year, int month, int dayOfMonth) {
            return new GregorianCalendar(year, month - 1, dayOfMonth).getTime();
        }
    };
    testBuilderAdd(factory);
    testBuilderPresent(factory);
    testBuilderAbsent(factory);
}