Hi,

In https://bugs.python.org/issue33531, Andrew Svetlov wrote "Fixed
failed sendfile tests on Windows (at least I hope so)." without giving
any bpo number or a commit number. So I looked at latest commits and I
found:

---
commit e2537521916c5bf88fcf54d4654ff1bcd332be4a
Author: Andrew Svetlov <andrew.svetlov@gmail.com>
Date:   Mon May 21 12:03:45 2018 +0300

    Fix asyncio flaky tests (#7023)
---

Please try to write better error messages for people who will dig into
the Git history in 1, 5 or 10 years:

* Usually, it's better to open a bug. Here you could give the full
error message, mention on which platform the test fails, etc.
* Mention which tests are affected
* Maybe even give an extract of the error message of the fixed test in
the commit message

I know that it's more effort and fixing flaky tests is annoying and
may require multiple iterations, but again, please think to people who
will have to read the Git history later...

I was able able to rebuild the context of this commit from a comment
of https://bugs.python.org/issue33531

Victor