[MAINT] run tests on parallel threads #18

	---
	# Runs tests suite with free threaded python.
	#
	###
	name: test free threaded python

	on:
	pull_request:
	workflow_dispatch:
	push:

	concurrency:
	group: ${{ github.workflow }}-${{ github.ref }}
	cancel-in-progress: true

	env:
	FORCE_COLOR: true

	jobs:

	free_threaded:
	name: 'Test with ${{ matrix.py }} on ${{ matrix.os }}'

	runs-on: ${{ matrix.os }}

	strategy:
	fail-fast: false
	matrix:
	py: [3.14t]
	os: [macos-latest, ubuntu-latest]
	env: [free_threaded]

	steps:
	- uses: actions/checkout@v6

	- name: Install the latest version of uv
	uses: astral-sh/setup-uv@v7

	- name: Setup python
	uses: actions/setup-python@v6
	with:
	python-version: ${{ matrix.py }}
	allow-prereleases: true

	- name: Install dependencies
	# for now one of the dependencies of plotly cannot be installed
	# for free threaded python so only testing with matplotlib
	#
	# for now one of the dependencies of plotly
	# cannot be installed for free threaded python
	# so only testing with matplotlib
	run: \|
	uv venv -p 3.14t
	source .venv/bin/activate
	uv pip install -e '.[test,dicomfs,indexed_gzip,spm,zstd]'
	uv pip install pytest-run-parallel

	- name: Run test suite
	# run on several threads
	# this may take a bit longer with fewer threads
	# but as some tests can be flaky,
	# they will more systematically fail with more threads
	id: test_free_threaded
	run: \|
	source .venv/bin/activate
	PYTEST_RUN_PARALLEL_VERBOSE=1
	N_THREADS=16
	pytest -ra --strict-config --strict-markers --showlocals --capture=no --parallel-threads $N_THREADS nibabel

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