Ever since the advent of multi-tier application architectures (which seems forever ago now), I’ve commonly had to work on tasks that span multiple levels of abstraction. You probably have too. For example, say you need to implement a new REST API call in your classic web application. You have to:
- Define the endpoint itself, with its request and response formats.
- Implement some business logic for it.
- Update the data layer to persist and/or query what needs it.
That’s just your three classic tiers, and sure, once you’ve done this sort of work enough, it’s almost straightforward. But, as time goes on and your application gets complicated, more aspects creep in. Security. Audit logging. Retries and resiliency. And then there’s all those newfangled microservices to deal with. The neat layer cake ends up looking more like monkey bread. How can you keep track of all of this and get your work done?
One way is to use something you should be doing anyway: writing unit tests.