As it turns out, we had this set of unit tests since 2018, but
so far they were not executed during the build verification.
Let's fix this:
* run unittest in discovery mode for all files in 'tests/' (commented out);
* rename this file, so it can be automatically detected and executed;
* properly import the API to be tested.
Currently 2 out of 16 unit tests are failing, so we need to get
them passing first and then uncomment the unittest execution.
Change-Id: I4d4facfabc75187acd5238ff4d0f26022bd58f82
4ae7c49076