Flaky tests

[p-schlickmann]

Hi team,

I understand the current state of the test suite is not ideal - some tests are flaky.

I'd love to help improve this. Ensuring test reliability should be a top priority, especially for an open-source tool that's the default queue mechanism in Rails 8.

@rosa I created this issue so we can discuss it further - do you have any advice or suggestions before I start digging in?

Thanks!

[rosa]

Hey @p-schlickmann, yes. All these tests that fork processes and rely on waiting on things to happen elsewhere are quite flaky indeed. I don't have any particular suggestions to start looking, I'm afraid, but any help here would be quite welcome!

[rosa]

Looks like the flakiest test after the last improvements is this one:

bin/rails test test/integration/instrumentation_test.rb:306

I tried to make it better in f433a99 but that didn't work so well. I'll look into it later.

[p-schlickmann]

Yea I noticed test/integration/processes_lifecycle_test.rb is also quite flaky - I'm working on it