Invariant-Driven Automated Testing
This work addresses the lack of effective automated testing mechanisms in microservice architectures, where existing API specifications such as OpenAPI suffer from limited semantic expressiveness and thus struggle to support high-coverage automated validation. To overcome this limitation, the authors propose APOSTL—an extension of OpenAPI grounded in restricted first-order logic—that enables formal annotation of semantic properties of APIs. Complementing this specification language, they develop PETIT, a tool that performs fully automated, source-code-free black-box testing using only APOSTL-annotated OpenAPI documents. By embedding formal logic directly into API specifications for the first time, this approach allows interface documentation to drive semantically precise and high-coverage automated tests, significantly enhancing the efficiency and reliability of microservice verification.