GitLab

* move the helper code into testing_utils

* port test_trainer_distributed to work with pytest

* improve docs

* simplify notes

* doc

* doc

* style

* doc

* further improvements

* torch might not be available

* real fix

* Apply suggestions from code review
Co-authored-by: Sylvain Gugger <35901082+sgugger@users.noreply.github.com>
Co-authored-by: Sylvain Gugger <35901082+sgugger@users.noreply.github.com>