ci: try using tox-uv

[henryiii]

Speeds up CI a little bit. Closes #858.

[FFY00]

Perhaps we could try using https://github.com/tox-dev/tox-gh?

[henryiii]

The hope here was to make the tests a bit faster; tox-gh might shorten the config, but wouldn't be faster (AFAIK). I don't understand why one test now uninstalls setuptools when it didn't before when running with tox-uv.

[layday]

Suggested change

	python-version: 3.12
	python-version: "3.12"

[henryiii]

Actually, I think this isn't needed anymore, since I changed tox to be installed via uv tool. Let's check that first.

[henryiii]

Interesting, the three failures are: AssertionError: Expected 'get_paths' to be called once. Called 4 times. from test_can_get_venv_paths_with_posix_local_default_scheme[False].

[layday]

Isn't venv always in SCHEME_NAMES, since 3.11?

[henryiii]

How does this test pass, then?

build/src/build/env.py

Lines 346 to 353 in e9adbf0

	if 'venv' in scheme_names:
	# Python distributors with custom default installation scheme can set a
	# scheme that can't be used to expand the paths in a venv.
	# This can happen if build itself is not installed in a venv.
	# The distributors are encouraged to set a "venv" scheme to be used for this.
	# See https://bugs.python.org/issue45413
	# and https://github.com/pypa/virtualenv/issues/2208
	paths = sysconfig.get_paths(scheme='venv', vars=config_vars)

seems to trigger a path that would fail this test.

[henryiii]

(get_paths.assert_called_once_with(scheme='posix_prefix', vars=mocker.ANY, specifically)