Building on what Phil Haack wrote a while ago to test your mvc routing. It is important to test your routing as it controls exactly where the users will go when they make a request. Especially if you have to maintain a complex CMS framework.
Haack used the moq framework to write a test helper method, I have modified his code to use NSubstitue, a different mocking framework:
This will build the routes table in your MVC application and we mock the request via HttpContextBase. The expectations should contain the key/value pairs you expect to be in the routeData.Values.
Below is an example unit test.
Hopefully this is easy to understand and helps you setup your unit tests quickly.