The three mental modes of working with unit tests

The other day, while pairing up on some unit test, I started to realize that I generally have three modes of looking at my unit tests.

The Writing Mode

While writing, I mostly focus on the mechanics of getting the test to pass. By then, I usually have a mental model and a particular scenario in mind, and my thoughts mostly focus on finding the most elegant syntax and structure to get my test from red to green. Since I already know the exact scenario, I don’t put too much attention on the name. If I’m really into the flow, the edge cases and alternative scenarios just pop into the back of my mind without me needing to really think about. In this mode, I also spend a lot of thoughts to come up with opportunities to refactor the test itself or the underlying constructs. For instance, is the scope of my test correct, does the subject-under-test not have too many dependencies. Since I practice Test Driven Development, some of these refactoring opportunities surface quick enough when I my set-up code explodes, or when my test code doesn’t communicate the intend anymore.

The Review Mode

While reviewing somebody’s pull request I switch to review mode in which I use the unit tests to understand the scope, the responsibilities and the dependencies of a class or set of classes. To understand those responsibilities, I put particular attention to the names of the tests thereby completely ignoring the implementation of the test itself. With the names as my only…