Category: Designing For Testability

Observability, at the class level, is about how easy it is to assert that the behavior of the functionality went as expected. My main advice is to ensure that your classes provide developers with simple and easy ways to assert their state. Does a class produce a list of objects you need to assert one…

At the architectural level, we saw that an important concern is to ensure that application (or domain) code is fully separated from the infrastructure code. At the class level, the most important recommendation I can give you is to ensure that classes are fully controllable (that is, you can easily control what the class under test does)…

I could spend pages discussing architectural patterns that enable testability. Instead, I will focus on what I consider the most important advice: separate infrastructure code from domain code. The domain is where the core of the system lies: that is, where all the business rules, logic, entities, services, and similar elements reside. Entities like Invoice and services such as ChristmasDiscount are examples…

I usually say that every software system can be tested. However, some systems are more testable than others. Imagine that for a single test case, we need to set up three different web services, create five different files in different folders, and put the database in a specific state. After all that, we exercise the feature…