Test Driven Development(TDD) is gaining momentum with each passing day. The reason for this is that with TDD we can not only built robust applications but also have a proof that the application is working correctly from a functional perspective by having successfully unit test cases on our modules. Also, the projects following agile/scrum methodology find TDD very useful because the major challenge in scrum is to define when our “done” is done. If we follow TDD approach then we know that when all our test cases are passed, we are done.
ASP.NET MVC application provide a very good support for TDD because we can write unit test directly against our controllers without needing any web server. Doing so we can be sure that the controllers are working correctly from a functionality perspective.
More info click here.
Hope this will help !!!