Many tests failing caused by changes of os.path.isabs() in Python 3.13 on Windows

[Jun Omae]

On Windows, isabs() no longer considers paths starting with exactly one slash (\ or /) to be absolute.

​What’s New In Python 3.13 — Python 3.13.3 documentation

Python 3.13

Python 3.13.3 (tags/v3.13.3:6280bb5, Apr  8 2025, 14:47:33) [MSC v.1943 64 bit (AMD64)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> import os.path
>>> os.path.isabs('C:/var')
True
>>> os.path.isabs('/var')
False
>>>

Python 3.12

Python 3.12.10 (tags/v3.12.10:0cc8128, Apr  8 2025, 12:21:36) [MSC v.1943 64 bit (AMD64)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> import os.path
>>> os.path.isabs('C:/var')
True
>>> os.path.isabs('/var')
True
>>>

Test results

======================================================================
ERROR: test_repository_providers_disabled (trac.upgrades.tests.db32.UpgradeTestCase.test_repository_providers_disabled)
Repository configuration is rewritten when repository providers
----------------------------------------------------------------------
Traceback (most recent call last):
  File "D:\a\trac\trac\trac\upgrades\tests\db32.py", line 150, in test_repository_providers_disabled
    db_provider.add_repository('repos3', '/var/git/repos3', 'git')
    ~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "D:\a\trac\trac\trac\versioncontrol\api.py", line 222, in add_repository
    raise TracError(_("The repository directory must be absolute"))
trac.core.TracError: The repository directory must be absolute

...

----------------------------------------------------------------------
Ran 2507 tests in 116.758s

FAILED (errors=49, skipped=17)