Problem 9.	DateTime.Now.AddDays();
Test the method DateTime.Now.AddDays(). Use mocking to provide the DateTime objects you need.
It is important that you test DateTime.Now, so don't use new DateTime() for the tests.
Some cases to consider:
•	Adding a day to the middle of the month, for example 16th June -> 17th June
•	Adding a day which will be in the next month (31st July -> 1st August)
•	Adding a negative value (-5 days), also check negative values which go on to the previous month
•	Adding a day to a leap year (28th February 2008 -> 29th February 2008)
•	Check the previous test with non-leap years (28th February 1900 -> 1st Match 1900)
•	Add a day to DateTime.MinValue and DateTime.MaxValue
•	Subtract a day from DateTime.MinValue and DateTime.MaxValue
You can also make other tests if you wish.