GH-71383: IDLE - Document testing subsets of modules

[terryjreedy]

• Issue: Eliminate 'ThemeChanged' warning when running IDLE tests #71383

[miss-islington]

Thanks @terryjreedy for the PR 🌮🎉.. I'm working now to backport this PR to: 3.11.
🐍🍒⛏🤖

[bedevere-bot]

GH-104464 is a backport of this pull request to the 3.11 branch.

[bedevere-bot]

⚠️⚠️⚠️ Buildbot failure ⚠️⚠️⚠️

Hi! The buildbot AMD64 Debian root 3.x has failed when building commit 080a596.

What do you need to do:

1. Don't panic.
2. Check the buildbot page in the devguide if you don't know what the buildbots are or how they work.
3. Go to the page of the buildbot that failed (https://buildbot.python.org/all/#builders/345/builds/4777) and take a look at the build logs.
4. Check if the failure is related to this commit (080a596) or if it is a false positive.
5. If the failure is related to this commit, please, reflect that on the issue and make a new Pull Request with a fix.

You can take a look at the buildbot page here:

https://buildbot.python.org/all/#builders/345/builds/4777

Failed tests:

• test_threading

Summary of the results of the build (if available):

==

Click to see traceback logs

remote: Enumerating objects: 9, done.        
remote: Counting objects:  11% (1/9)        
remote: Counting objects:  22% (2/9)        
remote: Counting objects:  33% (3/9)        
remote: Counting objects:  44% (4/9)        
remote: Counting objects:  55% (5/9)        
remote: Counting objects:  66% (6/9)        
remote: Counting objects:  77% (7/9)        
remote: Counting objects:  88% (8/9)        
remote: Counting objects: 100% (9/9)        
remote: Counting objects: 100% (9/9), done.        
remote: Compressing objects:  14% (1/7)        
remote: Compressing objects:  28% (2/7)        
remote: Compressing objects:  42% (3/7)        
remote: Compressing objects:  57% (4/7)        
remote: Compressing objects:  71% (5/7)        
remote: Compressing objects:  85% (6/7)        
remote: Compressing objects: 100% (7/7)        
remote: Compressing objects: 100% (7/7), done.        
remote: Total 9 (delta 2), reused 7 (delta 2), pack-reused 0        
From https://github.com/python/cpython
 * branch                  main       -> FETCH_HEAD
Note: switching to '080a5961527473af182b025bb29e0c52d43fd49e'.

You are in 'detached HEAD' state. You can look around, make experimental
changes and commit them, and you can discard any commits you make in this
state without impacting any branches by switching back to a branch.

If you want to create a new branch to retain commits you create, you may
do so (now or later) by using -c with the switch command. Example:

  git switch -c <new-branch-name>

Or undo this operation with:

  git switch -

Turn off this advice by setting config variable advice.detachedHead to false

HEAD is now at 080a596152 GH-71383: IDLE - Document testing subsets of modules (#104463)
Switched to and reset branch 'main'

configure: WARNING: pkg-config is missing. Some dependencies may not be detected correctly.

Fatal Python error: Segmentation fault

Thread 0x00007fb1dfb31280 (most recent call first):
  File "/root/buildarea/3.x.angelico-debian-amd64/build/Lib/unittest/runner.py", line 74 in _write_status
  File "/root/buildarea/3.x.angelico-debian-amd64/build/Lib/unittest/runner.py", line 95 in addSuccess
  File "/root/buildarea/3.x.angelico-debian-amd64/build/Lib/test/support/testresult.py", line 122 in addSuccess
  File "/root/buildarea/3.x.angelico-debian-amd64/build/Lib/unittest/case.py", line 648 in run
  File "/root/buildarea/3.x.angelico-debian-amd64/build/Lib/unittest/case.py", line 690 in __call__
  File "/root/buildarea/3.x.angelico-debian-amd64/build/Lib/unittest/suite.py", line 122 in run
  File "/root/buildarea/3.x.angelico-debian-amd64/build/Lib/unittest/suite.py", line 84 in __call__
  File "/root/buildarea/3.x.angelico-debian-amd64/build/Lib/unittest/suite.py", line 122 in run
  File "/root/buildarea/3.x.angelico-debian-amd64/build/Lib/unittest/suite.py", line 84 in __call__
  File "/root/buildarea/3.x.angelico-debian-amd64/build/Lib/unittest/suite.py", line 122 in run
  File "/root/buildarea/3.x.angelico-debian-amd64/build/Lib/unittest/suite.py", line 84 in __call__
  File "/root/buildarea/3.x.angelico-debian-amd64/build/Lib/unittest/runner.py", line 240 in run
  File "/root/buildarea/3.x.angelico-debian-amd64/build/Lib/test/support/__init__.py", line 1106 in _run_suite
  File "/root/buildarea/3.x.angelico-debian-amd64/build/Lib/test/support/__init__.py", line 1232 in run_unittest
  File "/root/buildarea/3.x.angelico-debian-amd64/build/Lib/test/libregrtest/runtest.py", line 294 in _test_module
  File "/root/buildarea/3.x.angelico-debian-amd64/build/Lib/test/libregrtest/runtest.py", line 330 in _runtest_inner2
  File "/root/buildarea/3.x.angelico-debian-amd64/build/Lib/test/libregrtest/runtest.py", line 373 in _runtest_inner
  File "/root/buildarea/3.x.angelico-debian-amd64/build/Lib/test/libregrtest/runtest.py", line 248 in _runtest
  File "/root/buildarea/3.x.angelico-debian-amd64/build/Lib/test/libregrtest/runtest.py", line 278 in runtest
  File "/root/buildarea/3.x.angelico-debian-amd64/build/Lib/test/libregrtest/main.py", line 365 in rerun_failed_tests
  File "/root/buildarea/3.x.angelico-debian-amd64/build/Lib/test/libregrtest/main.py", line 783 in _main
  File "/root/buildarea/3.x.angelico-debian-amd64/build/Lib/test/libregrtest/main.py", line 738 in main
  File "/root/buildarea/3.x.angelico-debian-amd64/build/Lib/test/libregrtest/main.py", line 802 in main
  File "/root/buildarea/3.x.angelico-debian-amd64/build/Lib/test/__main__.py", line 2 in <module>
  File "/root/buildarea/3.x.angelico-debian-amd64/build/Lib/runpy.py", line 88 in _run_code
  File "/root/buildarea/3.x.angelico-debian-amd64/build/Lib/runpy.py", line 198 in _run_module_as_main

Extension modules: _testcapi (total: 1)
Segmentation fault
make: *** [Makefile:1956: buildbottest] Error 139

Cannot open file '/root/buildarea/3.x.angelico-debian-amd64/build/test-results.xml' for upload