public void TimeElapsedInDaysSince_ValidGameDate_ReturnCorrectNumberOfDays()
        {
            //ARRANGE
            StandardDateTime time = new StandardDateTime(new System.DateTime(5196, 9, 1));
            //ACT
            long days = time.TimeElapsedInDaysSince(new StandardDateTime(new System.DateTime(5196, 11, 1, 1, 2, 0)));

            //ASSERT
            Assert.AreEqual(61, days);
        }
        public void TimeElapsedInDaysSince_InvalidGameDate_ReturnZero()
        {
            //ARRANGE
            StandardDateTime time = new StandardDateTime(new System.DateTime(5196, 7, 11));
            //ACT
            long days = time.TimeElapsedInDaysSince(new CustomDateTime(5196, 11, 1));

            //ASSERT
            Assert.AreEqual(0, days);
        }