I hope that all our readers are healthy and safe at this time of global uncertainty. In this issue, we have four regular research papers and three special sections. The first two regular research papers are linked by the common theme of software testing, whereas the final two regular papers report secondary research, the first being a survey of APIs and the second a systematic literature review concerned with refactoring. Testing is a crucial stage of the software development lifecycle. In “Increasing Validity Through Replication: An Illustrative TDD Case” , Adrian Santos, Sira Vegas, Fernando Uyaguari, Oscar Dieste, Burak Turhan, and Natalia Juristo draw attention to the importance of replication when performing software engineering experiments and also the agile software development process of test-driven development. The authors conclude that replication may improve the reliability of the previous findings and help to overcome the previous experiments’ weaknesses. Continuing with the theme of agile software development, the paper “Enhanced Regression Testing Technique for Agile Software Development and Continuous Integration Strategies” by Sadia Ali, Yaser Hafeez, Shariq Hussain, and Shunkun Yang proposes a test case prioritization and selection approach that was validated using an empirical study. The results show that the approach can enhance the regression testing process for agile development. In “What Are the Characteristics of Popular APIs? A Large-Scale Study on Java, Android, and 165 Libraries”, Caroline Lima and Andre Hora examine the characteristics of popular APIs. The authors report that popular APIs are different in that they tend to be larger, have more comments, and be more unstable than unpopular APIs. They also suggest some factors that developers can use to improve APIs. Systematic literature reviews can provide interesting insights of how a field has evolved over time. The paper “Automatic Software Refactoring: A Systematic Literature Review” by Abdulrahman Ahmed Bobakr Baqais and Mohammad Alshayeb provides an overview of papers that propose or implement an automated refactoring process. They found that most papers discuss code refactoring, with only a few recent papers focusing on model refactoring. Search-based refactoring is also now gaining popularity. Software Quality Journal https://doi.org/10.1007/s11219-020-09518-x

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我希望我们所有的读者在这个全球不确定的时刻都健康安全。在本期中，我们有四篇常规研究论文和三篇专题文章。前两篇常规研究论文与软件测试的共同主题相关联，而最后两篇常规论文报告了二次研究，第一篇是 API 调查，第二篇是与重构相关的系统文献综述。测试是软件开发生命周期的关键阶段。在“通过复制提高有效性：一个说明性的 TDD 案例”中，Adrian Santos、Sira Vegas、Fernando Uyaguari、Oscar Dieste、Burak Turhan 和 Natalia Juristo 提请注意执行软件工程实验和敏捷软件开发过程时复制的重要性测试驱动的开发。作者得出结论，复制可能会提高先前发现的可靠性，并有助于克服先前实验的弱点。继续以敏捷软件开发为主题，Sadia Ali、Yaser Hafeez、Shariq Hussain 和 Shukun Yang 的论文“用于敏捷软件开发和持续集成策略的增强回归测试技术”提出了一种测试用例优先级和选择方法，该方法已使用一项实证研究。结果表明，该方法可以增强敏捷开发的回归测试过程。在“流行API的特点是什么？“Java、Android 和 165 个库的大规模研究”，Caroline Lima 和 Andre Hora 研究了流行 API 的特征。作者报告说，流行的 API 的不同之处在于它们往往更大，有更多的评论，并且比不受欢迎的 API 更不稳定。他们还提出了一些开发人员可以用来改进 API 的因素。系统的文献综述可以为一个领域如何随着时间的推移而演变提供有趣的见解。Abdulrahman Ahmed Bobakr Baqais 和 Mohammad Alshayeb 的论文“自动软件重构：系统文献综述”概述了提出或实施自动重构过程的论文。他们发现大多数论文都在讨论代码重构，只有少数最近的论文专注于模型重构。基于搜索的重构现在也越来越流行。软件质量杂志 https://doi.org/10.1007/s11219-020-09518-x 系统的文献综述可以为一个领域如何随着时间的推移而演变提供有趣的见解。Abdulrahman Ahmed Bobakr Baqais 和 Mohammad Alshayeb 的论文“自动软件重构：系统文献综述”概述了提出或实施自动重构过程的论文。他们发现大多数论文都在讨论代码重构，只有少数最近的论文专注于模型重构。基于搜索的重构现在也越来越受欢迎。软件质量杂志 https://doi.org/10.1007/s11219-020-09518-x 系统的文献综述可以为一个领域如何随着时间的推移而演变提供有趣的见解。Abdulrahman Ahmed Bobakr Baqais 和 Mohammad Alshayeb 的论文“自动软件重构：系统文献综述”概述了提出或实施自动重构过程的论文。他们发现大多数论文都在讨论代码重构，只有少数最近的论文专注于模型重构。基于搜索的重构现在也越来越流行。软件质量杂志 https://doi.org/10.1007/s11219-020-09518-x 他们发现大多数论文都在讨论代码重构，只有少数最近的论文专注于模型重构。基于搜索的重构现在也越来越流行。软件质量杂志 https://doi.org/10.1007/s11219-020-09518-x 他们发现大多数论文都在讨论代码重构，只有少数最近的论文专注于模型重构。基于搜索的重构现在也越来越受欢迎。软件质量杂志 https://doi.org/10.1007/s11219-020-09518-x