Some tests are surprisingly slow #21
Description
The tests that run the trainer are much slower (locally) than running the trainer directly (locally). This concerns all tests in tests/test_train.py and tests/test_models_and_sweeps.py.
Currently, for that reason, they are marked as "slow" and are not run on github actions.
Perhaps we could parallelise them? See: https://stackoverflow.com/questions/74893304/how-do-i-speed-up-my-github-pytest-executions