Fix distutils.tests.test_register.RegisterTestCase.test_check_metadata_deprecated

[terryjreedy]

When testing 3.11.8 installed on Win 10, the only failure is

FAIL: test_check_metadata_deprecated (distutils.tests.test_register.RegisterTestCase.test_check_metadata_deprecated)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "C:\Programs\Python311\Lib\distutils\tests\test_register.py", line 295, in test_check_metadata_deprecated
    self.assertEqual(len(w.warnings), 1)
AssertionError: 71 != 1

Running test.test_distutils, the warnings are

C:\Programs\Python311\Lib\distutils\command\install.py:326:
DeprecationWarning: check_home argument is deprecated and ignored.

and apparently 70 similar to

C:\Programs\Python311\Lib\distutils\command\check.py:128: DeprecationWarning:
The frontend.OptionParser class will be replaced by a subclass of argparse.ArgumentParser in Docutils 0.21 or later.

I don't know why this passes on CI and buildbots, but there are two easy fixes.

1. Change the test to assertGreaterEqual(len(w.warnings), 1).
2. Remove the test.

@vstinner Which do you think would be better?

Linked PRs

• [3.11] gh-115198: Fix test_check_metadata_deprecation in test_distutils #115200
• [3.11] gh-115198: Fix support of Docutils >= 0.19 in distutils #115220

[serhiy-storchaka]

Please check whether #115200 helps.

[terryjreedy]

Yes (with changes).

[serhiy-storchaka]

The warnings are emitted by a newer version of Docutils. If Docutils is not installed, no warnings are emitted in this test and several other tests are skipped. According to them, this code will be broken in Docutils 0.21.

What should we do?

• Skip this test (and maybe several other tests) if docutils >= 0.21.
• Check the docutils version and raise more specific error for docutils >= 0.21.

But what if they will defer that change to later version? Testing this dynamically may be not easy because we do not know how exactly it will fail.

[serhiy-storchaka]

I looked in the docutils sources and try to fix it in other way: #115220.

[serhiy-storchaka]

On other hand, it is not compatible with the master branch of Docutils (future 0.21) due to other changes, so both PRs are equivalent: they fix tests with Docutils 0.19 and 0.20.

[terryjreedy]

Distutils is gone in 3.12. Are we ever going to run distutils tests (which is to say, 3.11 tests) with a future docutils? Are the docutils 0.21+ developers likely to do so, and care? IE, can we wait until a 0.21 problem arises? If we do wait, we could add a comment to test_check_metadata_deprecated: "# If this test breaks with docutils 0.21+, see issue 115198."