How did nordic mock headers like app_timer.h with many dependencies?

[Moustapha DIENG]

hello , I'm using Ceedling (Unity + Cmock) to integrate unit-testing on my embedded project but i face many issues to mock some nordic headers.

Can you please share some tips on how to mock headers like nrf_drv_gpiote.h or app_timer.h . These files have a lot of dependencies. When i use CMock or the fake function framework it take me a lot of time to mock the nordic headers, so maybe i missed something...

I'm using Ceedling, it will help me also if you can share your configuration file.

Thank you.

[WestCoastDaz]

I am also very interested in how Nordic does this.  I feel it would be beneficial to have blog post on this topic as TDD is extremely useful in embedded development but often not done due to complexity.

[Krzysztof Chruscinski]

We are using Unity with Cmock internally for unit testing in nrf5 sdk but it is wrapped into internal testing framework. I'm not sure what kind of issues you had with mocking headers that you mentioned (e.g. nrf_drv_gpiote.h). Header dependencies should not matter. It they are added to include path then they are just headers. They don't need to be mocked because functions from those API's aren't probably used by the module which is tested.

We have had 2 issues with mocking headers: mocking inline functions and mocking softdevice SVC calls. For both we made tweaks in cmock ruby script. However, in nRF Connect SDK we took different approach. Header which is supposed to be mocked is preprocessed initially (inline functions converted to standard function declarations, etc.). Modified headers must be included instead the original one. With this approach there is no need for modifying cmock ruby scripts. You can try similar approach if such exceptions need to be handled.

 nRF Connect SDK references:

- user guide: http://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/nrf/ug_unity_testing.html

- header conversion scripts: https://github.com/NordicPlayground/fw-nrfconnect-nrf/tree/master/scripts/unity

- unity/cmock support: https://github.com/NordicPlayground/fw-nrfconnect-nrf/tree/master/tests/unity 

[WestCoastDaz]

Krzysztof Chruscinski

Krzysztof Chruscinski said:

We have had 2 issues with mocking headers: mocking inline functions and mocking softdevice SVC calls. For both we made tweaks in cmock ruby script.

When you saw you had 2 issues with mocking headers as above, you were running your tests locally or on target nRF52?