Empirical Support for Two Refactoring Studies Using Commercial C# Software

Abstract

This paper documents a study of the application of refactorings in commercial C# software comprising 270 versions over a two-month period. The software was developed in a continuous integration environment in a large, multinational company where each software change committed to the source control was regarded as a new version. The aim of the research was to compare and contrast the results from two previous refactoring studies with those of the C# software. Method. A tool was developed to compare each version with the previous and detect occurrences of fifteen types of refactorings in both production and test classes. In total, over one thousand separate refactorings were identified. We then extended the profile of refactorings to compare (separately) the types of refactorings identified in test code and those in production code. Finally, we explored the interrelationships between a subset of the fifteen refactorings as a part explanation for the results. Conclusions. While 'simpler' refactorings were common, the more 'complex' structural refactorings were relatively rare. This supported the key result of an earlier empirical study by Advani et al. where Java open-source was used. Distinct differences were found in the types of refactoring applied to each code type. Support was found for a recent observation of Zaidman et al. in terms of parallel effort devoted to production and test classes. The study thus illustrates a strong commonality between refactoring trends found in both previous studies. Analysis of, and insight into all of our results were informed by follow-up discussions and consultation with the company's Architect.

On the diffusion of test smells and their relationship with test code quality of Java projects

“…Results indicated that considering the dependencies among tests is key for deciding whether refactor a test code. Gatrell et al 32 investigated test refactorings over 270 versions of commercial C# software, and results indicated that base refactorings are common and complex structural refactorings are relatively rare. Bleser et al 33 performed two empirical studies to analyze the diffusion of test smells at class level of 164 open‐source SCALA projects and assess the developers' perception of test smells.…”

Empirical Studies on Software Refactoring Techniques in the Industrial Setting

“…Gatrell, Counsell, and Hall [26] explored the difference between applying the refactoring in production classes and test classes. An empirical study presented to compare the findings from two prior refactoring studies by using versions anonymous commercial C# system from a large company.…”

“…Therefore, there are need to conduct more studies on them to confirm the current results. Furthermore, six studies ([3], [13], [26], [28], [30], [37]) explored the influence of the refactoring on the quality attributes in general without identifying which internal or external attribute have improved. Furthermore, to the best of our knowledge, there is lack of studies that require to investigate the refactoring impact on the several external quality attributes such as adaptability, analyzability, comprehensibility, completeness, effectiveness, flexibility, security, and extendibility.…”

House of Cards: Code Smells in Open-Source C# Repositories

“…Finally, there have been a few attempts to study code smells for the C# language [26], [27]. However, they lack both scale in terms of the number of projects they process and breadth of analysis in terms of the number of smells they examine.…”