Usable Verification of Object-Oriented Programs by Combining Static and Dynamic Techniques
With formal techniques becoming more and more powerful, the next big challenge is making software verification practical and usable. The Eve verification environment contributes to this goal by seamlessly integrating a static prover and an automatic testing tool into a development environment. The paper discusses the general principles behind the integration of heterogeneous verification tools; the peculiar challenges involved in combining static proofs and dynamic testing techniques; and how the combination, implemented in Eve through a blackboard architecture, can improve the user experience with little overhead over usual development practices. Eve is freely available for download. Even long-standing skeptics must acknowledge the substantial progress of formal methods in the last decades. Established verification techniques, such as those based on ax-iomatic semantics or abstract interpretation, have matured from the status of merely interesting scientific ideas to being applicable in practice to realistic programs and systems. Novel approaches have extended their domain of applicability beyond their original scope, providing new angles from which to attack the hardest verification challenges ; for example, model checking techniques, initially confined to digital hardware verification, are now applied to software or real-time systems. Other techniques, such as testing, have long been part of the standard development process, but only recently have they become first-class citizens of the verification realm, evolving in the case of random-based testing into rigorous, formal, and automatable approaches. Verification requires accurate specifications, and progress in this area has been no less conspicuous, with the development of understandable notations, such as those based on Design by Contract, which integrate seamlessly with the programming language and are amenable to static as well as dynamic analysis techniques. Finally, tool support has tremendously improved in terms of both reliability and performance, as a result of cutting-edge engineering of every component in the verification tool-chain as well as the increased availability of computing power. With the consolidation of these outstanding achievements , the new frontier is to make verification really usable by practitioners : the quest for high reliability to become a standard part of the software development process— " verification as a matter of course ". The present paper is a step towards this ambitious goal with two contributions, one general and one specific.