#37 Update tests for py3.13 and Windows and macOS

[adiroiban]

Fixes #37

This updates the test suite to run with Python 3.13.

The os.path.splitdrive behaviour was update to match the one for Python 3.11 and newer.... with a hackish backport for 3.9 and 3.10

It also enables the tests for GitHub Actions on Windows and macOS

To simplify testing, I have converted to code to run with pytest.

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some stdlib code was removed as it was deprecated in python 3.13

The plan is to use pytest for running the tests.

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The large file tests are disabled for now as they were not skipped by default for pytest.

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Also, flake8 tests are not triggered on GitHub Actions are there are many errors.

My plan is to use ruff instead of flake8 so that we can get automatic fixes.

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The contributing documentation was updated to no longer required tox.

It's hard to run local tests for all supported Python version and all supported operating systems.

As a start, you try to get the test passing using your preferred Python version.

On the PR is created, GitHub Action will trigger all the tests.

You can then check the result and see what needs to be done to fix the tests.

For example use use action-tmate to debug the tests and get access to Windows, Linux or macOS.

[adiroiban]

I am working on this on my fork to get all GitHub Action tests pass.

I am using this PR to document the reasoning behind the changes

Once all the tests pass, I will request a review.

[adiroiban]

All tests pass on win, macos and linux from py 3.9 to 3.13

you can check the result from GitHub Actions here adiroiban#1

[danifus]

Thanks for the updates. Looks pretty good from a quick review. I'll have a chance to look at this in more detail later this week