Testing

make test                                                              # serially
mpiexec -n 2 .venv/bin/python -m pytest --with-mpi src/mpifield/tests  # under MPI

Directory	Checks
src/mpifield/tests/unit	Field on one process: construction, data access, gather and scatter, arithmetic, gradients, smoothing, I/O, evaluation and plotting
src/mpifield/tests/parallel	that results do not depend on the split: deposits with halo exchanges, smoothing over halos, gradients, set_inside, I/O, run on any number of ranks
src/mpifield/tests/kernels	each kernel folder has all versions with one signature; Pyccel against NumPy; the parallel (OpenMP) deposit; the CUDA versions compiled as C++ on the CPU; the Metal versions (on Apple silicon with MLX)

Tests marked @pytest.mark.mpi(min_size=2) run only with --with-mpi (pytest-mpi). CI runs the suite serially on Python 3.10 to 3.13, and under mpiexec -n 2 and -n 4 with Open MPI.

A test directory must not be called mpi: pytest-mpi skips every test whose keywords contain “mpi” without --with-mpi, and the directory name is one of them.