In this issue

In this issue, we have six regular research papers. The first four are linked by the common theme of software defects and testing, whereas the fifth and sixth provide a review and an empirical study respectively. In “Fail-safe testing of safety-critical systems: a case study and efficiency analysis”, Ahmed Gario, Anneliese Andrews, and Seana Hagerman propose an approach for testing safetycritical systems based on the behavioural and fault models of the system. The approach leads to an integrated model which then can be used for test generation. The authors have developed a tool that estimates the number of states and transitions to show that the approach is scalable. Continuing with the theme of software defects, the paper “Predicting failures in agile software development through data analytics” by Feras A. Batarseh and Avelino J. Gonzalez introduces a method to predict software failures and their locations in agile sprints. Experiments showed that the new method for forecasting errors had a good success rate. In “Towards automation of IT systems repairs”, Janusz Gorski and Marek Kamiński describe a method of automating repairs in systems which can be integrated with any existing monitoring mechanism. A formal language (Z) is used to specify the method which was subsequently validated using a system that supports the operation of several hundred IT systems. The method provides a way ahead for the automation of repairs and monitoring of IT systems. Rounding off this section on software defects, the next paper acknowledges that software testing can be facilitated by software defect prediction. The paper “Tackling class overlap and imbalance problems in software defect prediction” by Lin Chen, Bin Fang, Zhaowei Shang, and Yuanyan Tang presents a new model to improve defect prediction which involves cleaning the data and then generating balanced subsets so that multiple classifiers can be trained on the data before building the final prediction model. The authors’ experiments showed that the proposed model provides reasonable defect prediction results. Turning to the requirements stage of software development, the authors Petra Heck and Andy Zaidman consider agile methods in their paper “A Systematic Literature Review on Software Qual J (2018) 26:1–2 https://doi.org/10.1007/s11219-018-9403-0