As a person who once struggled to parallelize a test suite when the entire thing was not written with parallelization in mind (until its runtime became onerous)... I would highly, highly recommend using some parallelization framework from the get-go to uncover any concurrency issues <i>immediately</i>.<p>In Elixir this is literally as simple as adding &quot;async: true&quot; to your test modules.<p>It will also force you to write tests that can run concurrently... which has a few nice side effects for your code design generally.