I have an existing asp.net webforms application that I would like to add some unit testing to but am unsure of exactly how to go about it.
The application is databas
I would most likely test the backing methods that your web forms call (bypassing the forms validation), this will let you test the logic and data access.
As for the test data, a seperate test database would be the best option. Otherwise i suggest having the test methods remove the test data once its completed.