Under the Hood: Developing Multicore Property-Based Tests for OCaml 5 | Tarides
In 2022, Multicore OCaml became reality. Programming on multiple threads brings new possibilities, but also new complexities. In order to foster confidence in OCaml 5 and retain OCaml's reputation as a trustworthy and memory-safe platform, Tarides has developed multicoretests: Two property-based testing libraries with a test suite built on top. This effort has successfully pinpointed a range of issues and contributed towards a stable multicore environment for the OCaml community to build on.
In this article and in the upcoming part two, I describe how we developed property-based tests for OCaml 5, the challenges we encountered, and the lessons we learned. Part one will focus mainly on the two open-source testing libraries STM and Lin, including some of our findings along the way. It may be of interest to both compiler hackers and library writers who are curious about how their code behaves under parallel usage.
In traditional unit testing, a developer asserts an expected result for a given input on a case-by-case basis. For example, when calling OCaml's floor : float -> float function with argument 0.5 we expect the result to be 0.:
