Handle skipped tests in coverage check

[RobinPicard]

We use the library coverage to check our test coverage in the CI. An issue we encountered is that skipped tests (for instance those related to mlx) are not taken into account such that the test fails even though we actually have a test for a given set of lines. A temporary solution is to exclude the files concerned from what coverage checks, but it's not the best. We should find a way of having coverage take into account those skipped tests.