#22 What is the right "unit" in unit testing and why it is not a class?

Whether you're just writing your first unit test or have been practicing Test Driven Development for many years, I'm sure your biggest challenge is to find the right scope for testing. Unfortunately a lot of books and guidance seem to imply that every class or type should be tested separately. Well, I can tell you from 15 years of unit testing experience that that's the best way to shoot yourself in the foot. In this session, I'm going to show you some concrete examples and why I chose a certain boundary for the "unit" in unit testing. I will also share design heuristics I use myself to find those boundaries and why those are not guidelines. I'll also illustrate how principals like DRY and SOLID can be both a blessing and a curse that may lead to the wrong design choices.