Open-Closed Principle

I recently read Mark Seemann’s post on how Testability is the Open-Closed Principle. This helped me realize the approach to testing directs the kinds of flexibility in our system, and behavior-based testing pushes the right kind of flexibility.

This is a throw back to one of my earlier wrestlings with the Open-Closed principle and writing extensible frameworks. The goal is to shed some light on an important realization that let me to understanding the Open-Closed Principle.