Evaluation of a Conceptual Framework for the Resilience of Unit Test Suites to Refactoring

Unit testing is widely recognized as a foundational practice in modern software engineering, championed by practitioners such as Kent Beck, Robert C. Martin, and Martin Fowler. While unit test suites are essential for supporting safe code evolution, they can also impede refactoring efforts when poorly designed or overly coupled to implementation details. This paper introduces a conceptual framework for understanding and evaluating the resilience of unit test suites to refactoring, inspired by principles from the field of resilience engineering. Drawing specifically from Donald Firesmith's Resilient System Framework in the cybersecurity domain, our model adapts the notions of passive and active resilience to characterize how unit tests can preserve their utility and trustworthiness amid structural code changes. We validate the pedagogical utility of this framework through a controlled experiment involving university students in a software testing course. The results suggest that resilienceoriented training improves students' ability to identify unit test suite quality issues and perform effective refactorings. This work contributes a novel theoretical lens for reasoning about the resilience of unit test suites to refactoring. It further provides practical guidance to integrate resilience thinking into software engineering education.