The test fails on Fedora:
https://buildbot.python.org/all/#/builders/185/builds/1028

vstinner@apu$ ./python -m test test_subprocess -m test_extra_groups -m test_group -v
== CPython 3.9.0a0 (heads/master:7cad53e6b0, Sep 13 2019, 11:42:25) [GCC 9.2.1 20190827 (Red Hat 9.2.1-1)]
== Linux-5.2.9-200.fc30.x86_64-x86_64-with-glibc2.29 little-endian
== cwd: /home/vstinner/python/master/build/test_python_14292
== CPU count: 8
== encodings: locale=UTF-8, FS=utf-8
Run tests sequentially
0:00:00 load avg: 0.38 [1/1] test_subprocess
test_extra_groups (test.test_subprocess.POSIXProcessTestCase) ... ERROR
test_group (test.test_subprocess.POSIXProcessTestCase) ... 
======================================================================
ERROR: test_extra_groups (test.test_subprocess.POSIXProcessTestCase)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/vstinner/python/master/Lib/test/test_subprocess.py", line 1840, in test_extra_groups
    output = subprocess.check_output(
  File "/home/vstinner/python/master/Lib/subprocess.py", line 419, in check_output
    return run(*popenargs, stdout=PIPE, timeout=timeout, check=True,
  File "/home/vstinner/python/master/Lib/subprocess.py", line 497, in run
    with Popen(*popenargs, **kwargs) as process:
  File "/home/vstinner/python/master/Lib/subprocess.py", line 889, in __init__
    gids.append(grp.getgrnam(extra_group).gr_gid)
KeyError: "getgrnam(): name not found: 'nogroup'"

======================================================================
ERROR: test_group (test.test_subprocess.POSIXProcessTestCase) (group='nogroup')
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/vstinner/python/master/Lib/test/test_subprocess.py", line 1800, in test_group
    output = subprocess.check_output(
  File "/home/vstinner/python/master/Lib/subprocess.py", line 419, in check_output
    return run(*popenargs, stdout=PIPE, timeout=timeout, check=True,
  File "/home/vstinner/python/master/Lib/subprocess.py", line 497, in run
    with Popen(*popenargs, **kwargs) as process:
  File "/home/vstinner/python/master/Lib/subprocess.py", line 862, in __init__
    gid = grp.getgrnam(group).gr_gid
KeyError: "getgrnam(): name not found: 'nogroup'"

----------------------------------------------------------------------

Ran 2 tests in 0.046s

FAILED (errors=2)
test test_subprocess failed
test_subprocess failed

== Tests result: FAILURE ==

1 test failed:
    test_subprocess

Total duration: 175 ms
Tests result: FAILURE