test_os / test_listdir failed as root-directory changed during test

[MatzeB]

BPO	39986
Nosy	@MatzeB
PRs	bpo-39986: Make test_listdir from test_os more robust #19035

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

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GitHub fields:

assignee = None
closed_at = None
created_at = <Date 2020-03-17.02:22:20.725>
labels = ['type-bug', 'tests', '3.9', '3.10', '3.11']
title = 'test_os / test_listdir failed as root-directory changed during test'
updated_at = <Date 2022-01-15.20:39:51.330>
user = 'https://github.com/MatzeB'

bugs.python.org fields:

activity = <Date 2022-01-15.20:39:51.330>
actor = 'iritkatriel'
assignee = 'none'
closed = False
closed_date = None
closer = None
components = ['Tests']
creation = <Date 2020-03-17.02:22:20.725>
creator = 'Matthias Braun'
dependencies = []
files = []
hgrepos = []
issue_num = 39986
keywords = ['patch']
message_count = 1.0
messages = ['364383']
nosy_count = 1.0
nosy_names = ['Matthias Braun']
pr_nums = ['19035']
priority = 'normal'
resolution = None
stage = 'patch review'
status = 'open'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue39986'
versions = ['Python 3.9', 'Python 3.10', 'Python 3.11']

[MatzeB]

The test_listdir test from Lib/test/test_os.py is using os.listdir() twice in the root directory with and without parameters and compares the results. I just had the test fail for me, because an unrelated process happened to create a file in the root directory between the two invocations of os.listdir. In my case it was rsyslog creating '/imjournal.state.tmp', but the problem is a general one.

The test failed with:

   ..test test_os failed -- Traceback (most recent call last):
  File "/home/matthiasb/dev/fbcpython/Lib/test/test_os.py", line 1914, in test_listdir
    self.assertEqual(set(os.listdir()), set(os.listdir(os.sep)))
AssertionError: Items in the first set but not the second:
'imjournal.state.tmp'

[duaneg]

It looks like this has been fixed (by listing a directory created by the test instead of root) as a side-effect of gh-71052 and can be closed.