[New-bugs-announce] [issue36692] Unexpected stderr output from test_sys_settrace

[Nick Coghlan]

New submission from Nick Coghlan <ncoghlan at gmail.com>:

The test output from test_sys_settrace makes it look like a couple of the async tracing tests aren't cleaning up after themselves properly:

```
[ncoghlan at localhost cpython]$ ./python -m test test_sys_settrace
Run tests sequentially
0:00:00 load avg: 1.27 [1/1] test_sys_settrace
unhandled exception during asyncio.run() shutdown
task: <Task finished name='Task-8' coro=<<async_generator_athrow without __name__>()> exception=RuntimeError("can't send non-None value to a just-started coroutine")>
RuntimeError: can't send non-None value to a just-started coroutine
unhandled exception during asyncio.run() shutdown
task: <Task finished name='Task-11' coro=<<async_generator_athrow without __name__>()> exception=RuntimeError("can't send non-None value to a just-started coroutine")>
RuntimeError: can't send non-None value to a just-started coroutine

== Tests result: SUCCESS ==

1 test OK.

Total duration: 102 ms
Tests result: SUCCESS

```

If that output is actually expected as part of the test, it would be helpful if the test printed a message beforehand saying to expect it. Otherwise, it would be desirable for the test to clean up after itself and keep the messages from being displayed in the first place.

----------
components: Tests
messages: 340608
nosy: asvetlov, ncoghlan, yselivanov
priority: low
severity: normal
stage: needs patch
status: open
title: Unexpected stderr output from test_sys_settrace
type: behavior
versions: Python 3.8

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Python tracker <report at bugs.python.org>
<https://bugs.python.org/issue36692>
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