What do you know about YOUR hexagonal architecture?

Last year on Devoxx, I had a talk with one of the engineers. He asked me: 'and do you have some tools or articles about hexagonal architecture? I heard that you are using it a lot at Allegro, and we are not sure if we are doing it right'. Yes, indeed, this is a very relevant question, also for Allegro developers! Hexagonal architecture (a.k.a. "ports and adapters") is easy to explain, but hard to master without some techniques that help you stay on the right track. If you are asking a similar question, or want to learn more about the hexagonal architecture in general, this presentation is for you.I will show you the unique relationship between hexagonal architecture, and your unit tests (and I don't mean ArchUnit, although we will briefly discuss this tool, too). Based on it, we will build a strategy with a set of techniques that will help you ensure you implemented this architectural pattern correctly. You can also easily teach those techniques your entire team regardless of the seniority level. This is not a presentation about frameworks or tools. The code examples are in Kotlin+Kotest, but the knowledge is general, and you can apply it to virtually any project in any technical stack in any system architecture (microservices, monoliths, and everything in between).