CPython 3.13.1 is breaking Windows CI

[ichard26]

Windows 3.13 CI is failing again due to upstream changes in CPython:

FAILED tests/unit/test_collector.py::test_ensure_quoted_url[file:///T:/path/with spaces/-file://///T:/path/with%20spaces] - AssertionError: assert 'file://///T:...ith%20spaces/' == 'file://///T:...with%20spaces'
  
  - file://///T:/path/with%20spaces
  + file://///T:/path/with%20spaces/
  ?                                +
FAILED tests/unit/test_urls.py::test_path_to_url_win[\\\\unc\\as\\path-file:////unc/as/path] - AssertionError: assert 'file://unc/as/path' == 'file:////unc/as/path'
  
  - file:////unc/as/path
  ?      --
  + file://unc/as/path

Taking a look at the changelog for 3.13.1, these are all of the potential bugfixes implicated:

• urllib.request.url2pathname() mishandles empty authority sections (mostly) python/cpython#126766
• urllib.request.url2pathname() mishandles a UNC URI variant python/cpython#127078
• pathname2url() does not work if path starts with // python/cpython#127217
• nturl2path.pathname2url() doesn't handle forward slashes python/cpython#120423
• urllib.request.pathname2url() and url2pathname() remove slashes on Windows python/cpython#126212
• urllib.request.pathname2url() mishandles UNC paths python/cpython#126205

cc @matthewhughes934 you've fixed a similar class of issues earlier. Would you be interested in taking a look at this?

[ichard26]

Ugh, alright. So, I think python/cpython#126208 and python/cpython#126214 are responsible for both failures respectively. They weren't merged at the same time so it's likely that there is a bugfix released where the UNC slash count change was made but not the trailing slash change. This makes rewriting the test cases to accommodate all of the various forms challenging.