Set TEST_MPI_RANKS to 2 as default #464

	---
	name: Testing on macOS
	on:
	push:
	branches:
	- 'develop'
	pull_request:

	jobs:
	build-and-test:
	runs-on: macos-latest

	strategy:
	matrix:
	use_mpi: [MPI=ON]
	use_openmp: [OPENMP=ON]
	use_smm: [SMM=blas]
	blas_impl: [accelerate,openblas]
	mpi_suffix: [openmpi]
	exclude:
	- use_mpi: MPI=OFF
	mpi_suffix: mpich

	steps:
	- uses: actions/checkout@v4
	with:
	fetch-depth: 0
	submodules: true

	- name: Install common dependencies
	run: \|
	env HOMEBREW_NO_AUTO_UPDATE=1 brew install \
	ninja

	- name: Install ${{ matrix.mpi_suffix }}
	run: \|
	env HOMEBREW_NO_AUTO_UPDATE=1 brew install ${{ matrix.mpi_suffix }}

	- name: Configure
	run: \|
	mkdir -p build
	cd build
	env \
	CC=gcc-14 CXX=g++-14 FC=gfortran-14 \
	cmake -G Ninja \
	-DCMAKE_BUILD_TYPE=Release \
	-DUSE_${{ matrix.use_mpi }} \
	-DUSE_${{ matrix.use_openmp }} \
	-DUSE_${{ matrix.use_smm }} \
	$([ "${{ matrix.blas_impl }}" = "openblas" ] && echo '-DCMAKE_PREFIX_PATH=/usr/local/opt/openblas') \
	-DMPIEXEC_PREFLAGS="$([ "${{ matrix.mpi_suffix }}" = "openmpi" ] && echo "-mca btl ^openib --allow-run-as-root")" \
	-DTEST_MPI_RANKS=auto \
	..

	- name: Build
	run: cmake --build build -- --verbose

	- name: Test
	run: \|
	cd build
	ctest --output-on-failure

	# vim: set ts=2 sw=2 tw=0 :

Provide feedback