Fix/flaky test

[PGijsbers]

Change

Working on #378. No changes so far, other than refactoring and using Path.write_text instead of io.write.
Setting up PR to test flakiness in CI, as I can't reproduce failures locally.

How to Test

Checklist

• Tests have been added or updated to reflect the changes, or their absence is explicitly explained.
• Documentation has been added or updated to reflect the changes, or their absence is explicitly explained.
• A self-review has been conducted checking:
  • No unintended changes have been committed.
  • The changes in isolation seem reasonable.
  • Anything that may be odd or unintuitive is provided with a GitHub comment explaining it (but consider if this should not be a code comment or in the documentation instead).
• All CI checks pass before pinging a reviewer, or provide an explanation if they do not.

Related Issues

[PGijsbers]

@andrejridzik Did this test fail consistently for you? Or at least consistently enough that you will have a good indication of whether or not things would be fixed. I cannot reproduce it at all and it now also not failing in CI... which leaves me at a loss. If you can reproduce it consistently, I would appreciate it if you could try and see if the test also fails for you on this branch.

edit: reproduced on CI now. Though not consistently which may make it hard to track down. Either way at least I know it's still present.

[andrejridzik]

I am still getting majority of failures with this setup. However, I was able to achieve 0% failure rate (n=100) when these two conditions are met:

1. sleep duration set to 10**-1
2. sleep moved to other location -> after file1.unlink()

Note: I got failure rate 11% when setting the sleep to 10**-2

[andrejridzik]

I did some experiments and got most reliable results when adding the sleep after this line.

[PGijsbers]

Interesting... Perhaps we'll need both. I'll move the sleep to where you suggested it and see if that's good enough for CI too (because clearly behavior of CI/CD doesn't match your environment 1:1)

[PGijsbers]

Needed both sleeps. I think should be good to go now @andrejridzik ?