> Right, but my question was very specifically about a test added for this issue.

This issue is about nanoseconds. I looked again and I found the commit  https://hg.python.org/cpython/rev/b0b4c4d365b1 related to this issue.

So to reply to your question, honestly, I don't recall why I had to replace sleep() with gmtime(): all I know is written in the comment. But Python internals changed *a lot* since 2015...

My comment is more general: closed issues are hidden from bugs.python.org home page, so only people in the nosy list get a notification. The discussion is "hidden". Since issue is 4 years old, some people in the nosy list no longer contribute to Python.

Moreover, the bug tracker is usually not a good place to ask a question. I prefer to only use it to discuss bugs.