Write regression test for issue #31; make it easier to write unit and regression tests
!9 (merged) fixes #31, but does not include a test.
It turns out writing tests for BasicRecsystem
is trickier than it should be. Some aspects of the API design make it difficult to mock things, and just test individual methods. The existing tests are more a suite of functional smoke tests that are designed to run in a particular order (see https://gitlab.lisn.upsaclay.fr/renewal/recsystems/-/blob/9d565bdf76ea348f357fd0a02697de74759d1c1e/renewal_recsystem/utils/testing/basic.py#L84)
That is, it needs to be easier to test individual methods on a recsystem instance without having to run the full server, etc.
But I'm pressed for time right now so will try to come back to this once higher priorities are addressed.