assert(DateTime(Date(1, 1, 1), TimeOfDay(12, 7, 0)).isAD);
assert(DateTime(Date(2010, 12, 31), TimeOfDay(0, 0, 0)).isAD);
assert(!DateTime(Date(0, 12, 31), TimeOfDay(23, 59, 59)).isAD);
assert(!DateTime(Date(-2010, 1, 1), TimeOfDay(2, 2, 2)).isAD);