The Impact of Pair Programming and Test-Driven Development on Package Dependencies in Object-Oriented Design - An Experiment

Background: Test-driven development (TDD) and pair programming are software development practices popularized by eXtreme Programming methodology. The aim of the practices is to improve software quality. Objective: Provide an empirical evidence of the impact of both practices on package dependencies playing a role of package level design quality indicators. Method: An experiment with a hundred and eighty eight MSc students fromWroclaw University of Technology, who developed finance-accounting system in different ways (CS — classic solo, TS — TDD solo, CP — classic pairs, TP — TDD pairs). Results: It appeared that package level design quality indicators (namely package dependencies in an object-oriented design) were not significantly affected by development method. Limitations: Generalization of the results is limited due to the fact that MSc students participated in the study. Conclusions: Previous research revealed that using test-driven development instead of classic (test-last) testing approach had statistically significant positive impact on some class level software quality indicators (namely CBO and RFC metrics) in case of solo programmers as well as pairs. Combined results suggest that the positive impact of test-driven development on software quality may be limited to class level.