public void TimeSlotDayArithmetic() { TimeSlot timeSlot = new TimeSlot(DayOfWeek.Tuesday, 20,0, "Court 1"); DateTime aSunday = new DateTime(2012,05,13); var reservation = timeSlot.MakeReservation(aSunday); Assert.IsTrue(reservation.At.DayOfWeek == DayOfWeek.Tuesday); }