With that out of the way, let’s consider what actually does qualify. Unit tests isolate and exercise specific units of your code. Okay. I’ll concede that I just punted by defining a term with a word in the term. But the creators of the term left the designation deliberately vague, presumably to cross language boundaries. In C#, you can think of a unit as a method. You thus write a unit test by writing something that tests a method. Oh, and it tests something specific about that method in isolation . Don’t create something called TestAllTheThings and then proceed to call every method in a namespace. That’s really it — all there is to it. You’ll notice that I haven’t mentioned a few things that might pop into your head, such as test-driven development (TDD), unit test frameworks , test runners, mocks, or other unit testing tools. Let’s not get ahead of ourselves. Forget TDD and mocks for another time,...