Large Software Product Lines (SPLs) are common in industry, thus introducing the need of practical solutions to test them. To this end, t-wise can help to drastically reduce the number of product configurations to test. Current t-wise approaches for SPLs are restricted to small values of t. In addition, these techniques fail at providing means to finely control the configuration process. In view of this, means for automatically generating and prioritizing product configurations for large SPLs are required. This paper proposes (a) a search-based approach capable of generating product configurations for large SPLs, forming a scalable and flexible alternative to current techniques and (b) prioritization algorithms for any set of product configurations. Both these techniques employ a similarity heuristic. The ability of the proposed techniques is assessed in an empirical study through a comparison with state of the art tools. The comparison focuses on both the product configuration generation and the prioritization aspects. The results demonstrate that existing t-wise tools and prioritization techniques fail to handle large SPLs. On the contrary, the proposed techniques are both effective and scalable. Additionally, the experiments show that the similarity heuristic can be used as a viable alternative to t-wise.

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We study the problem of model checking software product line (SPL) behaviours against temporal properties. This is more difficult than for single systems because an SPL with n features yields up to 2 n individual systems to verify. As each individual verification suffers from state explosion, it is crucial to propose efficient formalisms and heuristics.We recently proposed featured transition systems (FTS), a compact representation for SPL behaviour, and defined algorithms for model checking FTS against linear temporal properties. Although they showed to outperform individual system verifications, they still face a state explosion problem as they enumerate and visit system states one by one.In this paper, we tackle this latter problem by using symbolic representations of the state space. This lead us to consider computation tree logic (CTL) which is supported by the industry-strength symbolic model checker NuSMV. We first lay the foundations for symbolic SPL model checking by defining a feature-oriented version of CTL and its dedicated algorithms. We then describe an implementation that adapts the NuSMV language and tool infrastructure. Finally, we propose theoretical and empirical evaluations of our results. The benchmarks show that for certain properties, our algorithm is over a hundred times faster than model checking each system with the standard algorithm.