Recommending Faulty Configurations for Interacting Systems Under Test Using Multi-objective Search

Modern systems, such as cyber-physical systems, often consist of multiple products within/across product lines communicating with each other through information networks. Consequently, their runtime behaviors are influenced by product configurations and networks. Such systems play a vital role in our daily life; thus, ensuring their correctness by thorough testing becomes essential. However, testing these systems is particularly challenging due to a large number of possible configurations and limited available resources. Therefore, it is important and practically useful to test these systems with specific configurations under which products will most likely fail to communicate with each other. Motivated by this, we present a search-based configuration recommendation (SBCR) approach to recommend faulty configurations for the system under test (SUT) based on cross-product line (CPL) rules. CPL rules are soft constraints, constraining product configurations while indicating the most probable system states with a certain degree of confidence. In SBCR, we defined four search objectives based on CPL rules and combined them with six commonly applied search algorithms. To evaluate SBCR (i.e., SBCR_NSGA-II, SBCR_IBEA, SBCR_MoCell, SBCR_SPEA2, SBCR_PAES, and SBCR_SMPSO), we performed two case studies (Cisco and Jitsi) and conducted difference analyses. Results show that for both of the case studies, SBCR significantly outperformed random search-based configuration recommendation (RBCR) for 86% of the total comparisons based on six quality indicators, and 100% of the total comparisons based on the percentage of faulty configurations (PFC). Among the six variants of SBCR, SBCR_SPEA2 outperformed the others in 85% of the total comparisons based on six quality indicators and 100% of the total comparisons based on PFC.