Add GitHub workflow for Python unit tests #1

	name: Run Python tests

	on:
	push:
	# Run when a change to these files is pushed to any branch. Without the "branches:" line, for some reason this will be run whenever a tag is pushed, even if the listed files aren't changed.
	branches: ['*']
	paths:
	- 'python/**'
	- 'cime_config/SystemTests/**'
	- 'cime_config/buildlib/**'
	- 'cime_config/buildnml/**'
	pull_request:
	# Run on pull requests that change the listed files
	paths:
	- 'python/**'
	- 'cime_config/SystemTests/**'
	- 'cime_config/buildlib/**'
	- 'cime_config/buildnml/**'

	jobs:
	python-unit-tests:
	runs-on: ubuntu-latest
	steps:
	# Checkout the code
	- uses: actions/checkout@v4

	# Set up the conda environment
	- uses: conda-incubator/setup-miniconda@v3
	with:
	activate-environment: ctsm_pylib
	environment-file: python/conda_env_ctsm_py.yml
	channels: conda-forge
	auto-activate-base: false

	# Run Python unit tests check
	- name: Run Python unit tests
	run: \|
	cd python
	conda run -n ctsm_pylib ./run_ctsm_py_tests -u

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