Hi @ladislas @boraozgen,
I don’t know if you are already working with out-of-tree unit testing over Mbed OS 6, but I have just configured an example project which runs unit tests using mbed stubs and fakes but without including it in Mbed OS folder. This allows me to include tests in each library without modying mbed references.
As @ladislas said in this comment, it’s a good point copying Mbed OS configuration and modifying it to get out of the tree.
If you want more information, let me know!