This book constitutes the refereed proceedings of the 31st IFIP WG 6.1 International Conference on Testing Software and Systems, ICTSS 2019, held in Paris, France, in October 2019. The 14 regular papers and 3 short papers presented were carefully reviewed and selected from 30 submissions. This year also included an additional industrial paper. ICTSS is a series of international conferences addressing the conceptual, theoretic, and practical problems of testing software systems, including communication protocols, services, distributed platforms, middleware, embedded and cyber-physical systems, and security infrastructures.

This book constitutes the refereed proceedings of the 9th International Conference on Tests and Proofs, TAP 2015, held in L` Aquila, Italy, in July 2015, as part of the STAF 2015 Federated Conferences. The 11 revised full papers and 1 short papers presented together with 3 invited talks were carefully reviewed and selected from 21 submissions. The accepted papers contribute to various testing techniques (model-based, property-based, grammar-based, bounded-exhaustive), fault localization, model-driven engineering, as well as model coverage, consistency and validation, among others. Many papers rely on interactive and automatic theorem provers, including SMT solvers and model checkers.