The test case generation of Cyber-Physical Systems (CPSs) face critical challenges that traditional methods such as Model-Based Testing cannot deal with. As a result, simulation-based testing is one of the most commonly used techniques for testing CPSs despite sometimes being computationally too expensive. This paper proposes a search-based approach which is implemented on top of Non-dominated Sorting Genetic Algorithm II (NSGA-II), the most commonly applied multi-objective search algorithm for cost-effectively generating executable test cases in order to test CPSs. With the aim of guiding the generation of the optimal set of so-called reactive test cases, the approach formally defines three cost-effectiveness measures: requirements coverage, test case similarity and test execution time. Furthermore, we design one crossover operator and three mutation operators (i.e., mutation at test suite level named Mu TS, mutation at test case level named Mu TC and mutation at both levels named Mu BO) for test case generation. We evaluate our approach by comparing with Random Search (RS) using four case studies (one of them is an industrial system). Moreover, we evaluate the three mutation operators using the four case studies. The results of the experiment (with a rigorous statistical analysis) indicated that our approach in conjunction with the crossover operator operation and three mutation operators significantly outperformed RS. In general, Mu BO achieved the best performance among the three mutation operators and managed to improve on average the test execution time by 14%, the requirements coverage by 34%, and the test similarity by 75% as compared with RS.

Variability is a key aspect in software product lines. Functional variability has been largely studied as a way to obtain all the desired products for a line. Quality variability, less understood and more complex, has not received so much attention by researchers. However, different members of the line may require different levels of a quality attribute. The design phase is a good point to assure that quality attributes requirements are met within the product line so this means paying attention to software architecture evaluation during domain engineering. The quality evaluation in software product lines is much more complicated than in single-systems as products can require different quality levels and the product line can have variability on design that in turn affects quality. The evaluation of all the products of a line is very expensive. Thus, ways of reducing the evaluation efforts are necessary. Herein is presented a method for facilitating cost-effective quality evaluation of a product line taking into consideration variability on quality attributes.

Cyber-Physical Systems (CPSs) can be found in many sectors (e.g., automotive and aerospace). These systems are usually configurable to give solutions based on different needs. The variability of these systems is large, which implies they can be set into millions of configurations. As a result, different testing processes are needed to efficiently test these systems: the appropriate configurations must be selected and relevant test cases for each configuration must be chosen as well as prioritized. Prioritizing the order in which the test cases are executed reduces the time for detecting faults in these kinds of systems. However, the test suite size is often large and exploring all the possible test case orders is infeasible. Search algorithms can help find optimal solutions from a large solution space. This paper presents an approach based on weight-based search algorithms for prioritizing the test cases for configurable CPSs. We empirically evaluate the performance of the following algorithms with two case studies: Weight-Based Genetic Algorithms, Random Weighted Genetic Algorithms, Greedy, Alternating Variable Method and Random Search (RS). Our results suggest that all the search algorithms outperform RS, which is taken as a baseline. Local search algorithms have shown better performance than global search algorithms.