gh-119949: refactor test_exc() helper in test_format.py

[skirpichev]

Use assertRaisesRegex() context and fix #119781 (review)

• Issue: test_exc() helper in test_format.py doesn't fail if exception message unexpected #119949

[skirpichev]

CC @serhiy-storchaka

[skirpichev]

CC @JelleZijlstra, It's a follow-up of pr #119781

[serhiy-storchaka]

To minimize the diff, you can add methods, and then use local variables as aliases.

def _test_exc(self, formatstr, args, exception, excmsg):
    ...

def test_something(self):
    test_exc = self._test_exc
    ...

[read-the-docs-community]

Documentation build overview

📚 cpython-previews | 🛠️ Build #32820228 | 📁 Comparing ab1af9d against main (a7d5a6c)

  🔍 Preview build  

479 files changed · ± 447 modified · - 32 deleted

± Modified

• about.html
• bugs.html
• glossary.html
• index.html
• license.html
• py-modindex.html
• c-api/allocation.html
• c-api/apiabiversion.html
• c-api/arg.html
• c-api/buffer.html
• and 437 more...

- Deleted

• improve-page-nojs.html
• improve-page.html
• _static/tachyon-example-flamegraph.html
• _static/tachyon-example-heatmap.html
• c-api/curses.html
• c-api/extension-modules.html
• c-api/interp-lifecycle.html
• c-api/picklebuffer.html
• c-api/profiling.html
• c-api/sentinel.html
• and 22 more...

[skirpichev]

To minimize the diff, you can add methods, and then use local variables as aliases.

Done. Unfortunately, some tests still should be changed due to using assertRaisesRegex instead of string comparison.

[serhiy-storchaka]

You can use re.escape() to minimize the diff.

[serhiy-storchaka]

LGTM. 👍

[miss-islington-app]

Thanks @skirpichev for the PR, and @serhiy-storchaka for merging it 🌮🎉.. I'm working now to backport this PR to: 3.14, 3.15.
🐍🍒⛏🤖

[miss-islington-app]

Sorry, @skirpichev and @serhiy-storchaka, I could not cleanly backport this to 3.14 due to a conflict.
Please backport using cherry_picker on command line.

cherry_picker 0851700a9d99ca4bebd8d5f9d73c8c9ab1084405 3.14

[bedevere-app]

GH-150329 is a backport of this pull request to the 3.15 branch.

[skirpichev]

@serhiy-storchaka, I think it doesn't make sense to backport this for 3.14 as #142081 wasn't backported.