tests/test_process.py::TestAsyncio_AIO_Process::test_cancel_post_init fails randomly

[Aleksanaa]

Found when building on NixOS:

tests/test_process.py .......................................................Unexpected calls to loop.call_exception_handler():
[{'exception': InvalidStateError('invalid state'),
  'handle': <Handle _UnixWritePipeTransport._call_connection_lost()>,
  'message': 'Exception in callback '
             '_UnixWritePipeTransport._call_connection_lost()'},
 {'exception': InvalidStateError('invalid state'),
  'handle': <Handle _UnixReadPipeTransport._call_connection_lost()>,
  'message': 'Exception in callback '
             '_UnixReadPipeTransport._call_connection_lost()'},
 {'exception': InvalidStateError('invalid state'),
  'handle': <Handle BaseSubprocessTransport._call_connection_lost()>,
  'message': 'Exception in callback '
             'BaseSubprocessTransport._call_connection_lost()'}]
F......................
tests/test_process_spawning.py .
tests/test_regr1.py s
tests/test_runner.py ..
tests/test_signals.py .....................
tests/test_sockets.py ......................s..........
tests/test_tcp.py .......................s.......................................................s.sss.ssss.sss.ss..ssssssss
tests/test_testbase.py ...
tests/test_udp.py ..................ss...
tests/test_unix.py ..............s.s.................

=================================== FAILURES ===================================
________________ TestAsyncio_AIO_Process.test_cancel_post_init _________________
Traceback (most recent call last):
  File "/nix/store/48ak878425b9wyrkwd826d2043m3ii36-python3-3.13.11/lib/python3.13/unittest/case.py", line 58, in testPartExecutor
    yield
  File "/nix/store/48ak878425b9wyrkwd826d2043m3ii36-python3-3.13.11/lib/python3.13/unittest/case.py", line 654, in run
    self._callTearDown()
    ~~~~~~~~~~~~~~~~~~^^
  File "/nix/store/48ak878425b9wyrkwd826d2043m3ii36-python3-3.13.11/lib/python3.13/unittest/case.py", line 611, in _callTearDown
    self.tearDown()
    ~~~~~~~~~~~~~^^
  File "/nix/store/f10g6ix3rxlnh10aq4yrmyixgnw215lm-python3.13-uvloop-0.22.0/lib/python3.13/site-packages/uvloop/_testbase.py", line 327, in tearDown
    super().tearDown()
    ~~~~~~~~~~~~~~~~^^
  File "/nix/store/f10g6ix3rxlnh10aq4yrmyixgnw215lm-python3.13-uvloop-0.22.0/lib/python3.13/site-packages/uvloop/_testbase.py", line 106, in tearDown
    self.fail('unexpected calls to loop.call_exception_handler()')
    ~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/nix/store/48ak878425b9wyrkwd826d2043m3ii36-python3-3.13.11/lib/python3.13/unittest/case.py", line 732, in fail
    raise self.failureException(msg)
AssertionError: unexpected calls to loop.call_exception_handler()
=========================== short test summary info ============================
FAILED tests/test_process.py::TestAsyncio_AIO_Process::test_cancel_post_init - AssertionError: unexpected calls to loop.call_exception_handler()
===== 1 failed, 405 passed, 39 skipped, 8 deselected in 157.00s (0:02:36) ======

Debian maintainers also discussed about this failure: https://www.mail-archive.com/debian-bugs-dist%40lists.debian.org/msg2072110.html

It won't happen every time, but about half the time.

python 3.13.11 or 3.14.2
uvloop 0.22.0