Quality in structural interdependencies between software components
A testable architecture is a rule-based design system structurally open to change and to testing. Easy to test also means easy to change, while easy to change should makes tests more stable. Being open to change and testing is a design way.
The SOLID principles in object-oriented design foster the creation of software systems with strong cohesion and loose coupling to fight against software rot.
Change is absorbed by source code as a liquid may penetrate into an architectural structure. It may happen in chaos or with science. The SOLID principles guide change softly.
