Hello Dario,

I am going to include general information for those that may see this and want more information about how unit testing works. For those that apply to that see our documentation on Unit testing here:
https://docs.q2developer.com/guides/code_quality/unit_testing.html

For your specific application and a lot of other applications where mocking functions, objects, modules, attributes, and many other things see the pytest documentation here:
https://docs.pytest.org/en/latest/how-to/monkeypatch.html

The Caliper SDK has excellent unit test coverage, so if you are looking for examples for other pieces of code I recommend looking here:
https://gitlab.com/Q2Antilles/q2-sdk

-Trey