First diff exposing the work I have done so far on improving swh-web tests.
This one is about the tests data generation by populating an in-memory archive.
In order to avoid harcoding tests input data and get closer to real world ones,
populate a test archive by loading in it a couple of lightweight git repositories.
The ids of the objects in this test archive (contents, directories, revisions, ...)
will then be provided as tests input in order to retrieve their associated data
from the in-memory storages. Proceeding like this will allow us to remove a
lot of mocks in the tests implementation.