Handle differences in UNC path parsing when generating extractPackages

[mhsmith]

Closes #1087 by simply skipping over any test_sources items whose basename is empty. Since these are incomplete paths, briefcase create android should already give an appropriate error message when it tries to copy them into the app, and this behavior hasn't changed. So I've marked the changenote as misc.

PR Checklist:

• All new features have been tested
• All new features have been documented
• I have read the CONTRIBUTING.md file
• I will abide by the code of conduct

[rmartin16]

Tests are failing for me locally on Python 3.11.2. Just reran CI for windows-3.11 and 3.11.2 has not landed yet.

briefcase on  extract-packages-unc [!?] via 🐍 v3.11.2 (venv-3.11.2-briefcase) took 2s
❯ python -V
Python 3.11.2

briefcase on  extract-packages-unc [!?] via 🐍 v3.11.2 (venv-3.11.2-briefcase)
❯ pytest -k test_extract_packages
...............F..................F...
==============================================================================
FAIL: tests/platforms/android/gradle/test_create.py::test_extract_packages[test_sources15-]
------------------------------------------------------------------------------
test_sources=['//leading']
context['extract_packages']='"leading"'
expected=''

Traceback (most recent call last):
  File "C:\Users\user\github\beeware\briefcase\tests\platforms\android\gradle\test_create.py", line 126, in test_extract_packages
    assert context["extract_packages"] == expected
AssertionError: assert '"leading"' == ''
  + "leading"

==============================================================================
FAIL: tests/platforms/android/gradle/test_create.py::test_extract_packages[test_sources34-]
------------------------------------------------------------------------------
test_sources=['\\\\leading']
context['extract_packages']='"leading"'
expected=''

Traceback (most recent call last):
  File "C:\Users\user\github\beeware\briefcase\tests\platforms\android\gradle\test_create.py", line 126, in test_extract_packages
    assert context["extract_packages"] == expected
AssertionError: assert '"leading"' == ''
  + "leading"

------------------------------------------------------------------------------
Ran 38 tests in 1.87s

FAILED (failures=2)

[rmartin16]

scratch that; 3.11.2 has dropped but actions/setup-python will use a locally cached version of Python if one already exists on the runner.

Using check-latest: true would force actions/setup-python to always use the most recent release of a Python version.

[freakboy3742]

Using check-latest: true would force actions/setup-python to always use the most recent release of a Python version.

Good to know, but I don't think it's worth it here. We're not that sensitive to point updates that it's essential that every PR is tested against the very latest possible release.

[freakboy3742]

Makes sense, and I can't argue with a passing test suite.

[rmartin16]

Using check-latest: true would force actions/setup-python to always use the most recent release of a Python version.

Good to know, but I don't think it's worth it here. We're not that sensitive to point updates that it's essential that every PR is tested against the very latest possible release.

I agree; however, here, the test suite ran against Python 3.11.1. We need this test suite to run against Python 3.11.2 to test the changes.

[freakboy3742]

🤦

I missed the significance of what you were saying. I guess this means we'll see another CI failure in the near future... apologies for the confusion and premature merge.