@pcorpet I am not very familiar with the code base.

• I see that the code is sustained in one style, is clean and without obvious mistakes.
• I've installed mongomock from the feature branch and enabled my not-yet-passing unit test, and it works as expected.

If anyone is interested in testing:
pip install git+https://github.com/pcorpet/mongomock.git@set-pipeline

FYI,
While trying to post this comment with Reviewable, got this error:

Failed to publish: GitHub error 404 on POST https://api.github.com/repos/mongomock/mongomock/pulls/574/reviews: Not Found (The mongomock organization may need to authorize Reviewable as an accepted third party application.)