Analyzing Application Risk

Unit tests help us us drive out intra-class functionality and build confidence in our incremental changes. Integration tests help us ensure that our inter-class and inter-app configuration works as a system.

But neither of these test types presents a panacea for helping us save time and avoid worry: unit tests are relatively slow to drive out, and they tend to end up micro-managing our implementation choices. Integration tests give us a long feedback loop, and they tend to produce a lot of false positives for problems.

Instead, we can consider the risks present in our system as a whole, then write a test harness that mitigates the largest risks and communicates those risks to the rest of the team. This risk-focused perspective, over time, makes it easier for you and your teammates to spot and preempt the kinds of bugs that could become headaches later.