Software Engineering
Design for Testability
If your tests are brittle, verbose, or hard to maintain — or if Test Driven Development feels like an uphill struggle — the root cause is almost always the same: the code was not designed with testability in mind. This course fixes that.
Design for Testability is not about testing techniques. It is about the structural properties of code that make it easy — or difficult — to test. You will learn why testable code is inherently better code: the same principles that make a system testable also make it easier to understand, extend, and evolve. Teams that apply these principles consistently ship faster, accumulate fewer defects, and spend far less time firefighting.
The course walks through ten concrete tools — from decomposition and information hiding to configurability, deployability, and system-level observability — showing how each one improves both testability and overall design quality. It closes with a practical look at common anti-patterns (monkey patching, test hooks, singletons) that quietly undermine testability even in well-intentioned codebases.
What's covered
- Observability & controllability
- Decomposition
- Design by contract
- Modularity
- Information hiding
- Configurability
- Simple design
- Incremental development
- Deployability
- Automation
- System observability
- Anti-patterns