I have written a Windows Forms application and now I want to write some unit tests for it (not exactly test driven development seeing as I am writing the tests after I have developed but better late then never!) My question is that with such an application how do you go about writing the unit tests, given that nearly all of the methods and events are private? I have heard of NUnit Forms but I hear good and bad things about it, also there has been no real development on that project for a while so it looks abandoned. Also is it generally accepted that the project have have adequate unit testing in place if I wrote unit test cases for all of the events that a user would trigger by clicking/ pressing buttons, or would I have to go and write unit test cases for all methods and figure out a way to test my private methods?
EDIT: My business logic is seperated from my presentation logic, there is 1 or 2 public methods my business logic exposes so the form can access them, but what about all the private methods that are in the business logic?
The first thing I would do is to ensure that you have proper separation of your business logic from your form. Basically, using an MVC pattern. Then, you can easily test everything outside the form, as if the form didn’t even exist.
Now, this could still leave some untested form-specific functionality. I.E., is the form wired-up to the service correctly? For this, then you could still consider something like NUnit Forms or another alternative.