UCov : A Static Analysis Tool for API Usage Coverage Validation

Sammanfattning: Nowadays, all software projects are based on a large number of libraries, so they do not have to start from scratch. These libraries evolve over time, whether to add functionality or to simplify their use. These updates are necessary to improve their libraries, but can lead to errors in their clients’ code. Developers are thus faced with the problem of breaking changes and need to be able to inform their clients as soon as possible of the arrival of these changes. To limit the impact of these breaking changes, this Master thesis presents UCov. UCov is a static analysis tool that gives library developers a quick overview of the usage coverage of their tests compared with the coverage of their clients. This lets them to compare which elements of their library are being tested with those being used by their clients and also how they are being used. This will enable developers to improve their test suite according to how their clients use their library, to get a better overview of how their library is used, and also to give their clients the best possible warning of changes that may impact their code, thanks to release notes. In this study, we explain the implementation of UCov and test it on various libraries. The results obtained on these libraries are satisfactory. They enable us to highlight potential breaking changes. They also show that there are elements of the libraries’ APIs that are used by clients but never tested. Finally, these results show that UCov offers developers a new tool enabling them to limit the impact of their breaking changes by gaining a better understanding of how clients use their libraries.