Evolution analysis of software quality metrics in an open-source java project: A case study on TestNG

TL;DR

This paper analyzes how software quality metrics evolved over five versions of the open-source Java framework TestNG, revealing trends toward increased stability and maintainability through static analysis and statistical methods.

Contribution

It provides a detailed case study of software quality evolution in TestNG, highlighting structural trends and offering insights for maintaining code quality in similar projects.

Findings

TestNG became more stable and maintainable over versions

Structural complexity decreased with refactoring and architectural improvements

Metrics analysis revealed clear evolution patterns in software quality

Abstract

Software quality is critical in modern software engineering, especially in large and evolving codebases. This study analyzes the evolution of software quality metrics in five successive versions of the open-source Java testing framework TestNG. Using the static analysis tool Understand, eleven key object-oriented metrics, including cyclomatic complexity, class coupling, and lines of code, were extracted for each version. Statistical and visual analyses reveal structural trends over time. The results indicate that TestNG has matured into a more stable and maintainable framework, reflecting ongoing development, refactoring, and architectural improvements. This study provides insights into design evolution and offers recommendations for maintaining code quality in similar projects.