Synthesizing adaptive test strategies from temporal logic specifications

Constructing good test cases is difficult and time-consuming, especially if the system under test is still under development and its exact behavior is not yet fixed. We propose a new approach to compute test cases for reactive systems from a given temporal logic specification. The tests are guaranteed to reveal certain simple bugs (like occasional bit-flips) in every realization of the specification and for every behavior of the uncontrollable part of the system's environment. We aim at unveiling faults for the lowest of four fault occurrence frequencies possible (ranging from a single occurrence to persistence). Based on well-established hypotheses from fault-based testing, we argue that such tests are also sensitive for more complex bugs. Since the specification may not define the system behavior completely, we use reactive synthesis algorithms (with partial information) to compute adaptive test strategies that react to behavior at runtime. We work out the underlying theory and present first experiments demonstrating that our approach can be applied to industrial specifications and that the resulting strategies are capable of detecting bugs that are hard to detect with random testing.