Add more unit tests in the `get_app` function, document chaining #358

	name: Radical tests
	on:
	pull_request:
	types:
	- opened
	- synchronize

	jobs:
	build-linux:
	runs-on: ubuntu-24.04
	timeout-minutes: 60
	strategy:
	max-parallel: 5

	steps:
	- uses: actions/checkout@v4

	- name: Set up Python 3.11
	uses: actions/setup-python@v3
	with:
	python-version: '3.11'

	- name: Add conda to system path
	run: \|
	# $CONDA is an environment variable pointing to the root of the miniconda directory
	echo $CONDA/bin >> $GITHUB_PATH
	echo "CONDA BIN: $CONDA/bin"

	- name: Install parsl and dependencies
	run: \|
	conda install --channel=conda-forge mpich mpi4py openssl
	make deps
	pip3 install ".[radical-pilot]"
	export PATH=/usr/share/miniconda/bin/:$PATH

	- name: Sanity check
	run: \|
	echo "PATH: $PATH"
	echo "Python: "; which python3
	mpiexec --version
	mpiexec -n 4 python3 -c "from mpi4py import MPI; assert MPI.COMM_WORLD.Get_size() == 4, 'Expected 4 ranks'; print(f'Rank {MPI.COMM_WORLD.Get_rank()} of {MPI.COMM_WORLD.Get_size()}')"

	- name: Run pytest suite for Radical
	run: \|
	export RADICAL_CI=1
	make radical_local_test

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