A Satisfiability-Based Approach to Generation of Constrained Locating Arrays

A locating array is a mathematical object that is intended to be used for fault localization in combinatorial interaction testing. However, applying it to a real-world testing is difficult because a system under test often has constraints among test parameter values. Test cases must satisfy such constraints to be executed; but the definition of locating arrays does not consider constraints. Hence directly using a locating array as a test suite results in interactions that are not tested as well as faulty interactions that cannot be identified. In this paper, we propose a method of generating Constrained Locating Arrays (CLAs), which are a constraint-aware extension of locating arrays. The proposed method uses a Satisfiability Modulo Theories (SMT) solver to search for a CLA. Experimental results show that the proposed method is often fast enough to find a minimum CLA for a nontrivial case.