A testable alternative to DateTime.Now
PM> Install-Package System.Clock
Now use System.Clock.Now
instead of System.DateTime.Now
//freeze time
System.Clock.Freeze();
//freeze at a specific time
System.Clock.Freeze(new DateTime(2012, 12, 21));
//return time to the present
System.Clock.Unfreeze();
Inspired by Ayende Rahien's SystemTime