Finding Minimum Locating Arrays Using a SAT Solver

Locating arrays provide combinatorial test suites not only for detecting the presence of an interaction fault but also for locating the fault. Compared with test suites for ordinary combinatorial testing, however, the fault locating capability entails a substantial increase in the size of test suites. In this position paper, we consider the problem: how small can locating arrays be? To answer the question, we develop a method that finds a locating array of a given size using a SAT solver. We report the size of the smallest locating arrays discovered by using our method. This result provides the smallest known upper bound on the size of the minimum locating arrays.