This is not an app testing, but a Micro:Bit code testing and debugging. I think that process can be applicable to any kind of programming language. On this site there are lesson plans on how to code but also testing and debugging as well as ways to evaluate students knowledge.

https://microbit.org/de/assets/globalchallenge/walking-for-water-lesson-2/walking-for-water-lesson-2-lesson-plan.docx