The Matrix Market tests read matrices that test/CMakeModules/download_sparse_datasets.cmake downloads from the SuiteSparse Matrix Collection, whose storage refuses every download. ArrayFire's arrayfire-data repository holds the same files, unchanged, under matrixmarket/, with their license (CC BY 4.0) and citations.

matrixmarket.json pins the arrayfire-data commit that CI downloads them from, and records each matrix's size and SHA-256, and its original SuiteSparse URL and archive SHA-256. Before every build, ci.sh runs .github/scripts/check-matrix-data.py:

• While commit is empty, it prints that no commit is pinned, and the Matrix Market tests are off (AF_TEST_WITH_MTX_FILES=OFF).
• With a commit, it downloads each matrix from https://raw.githubusercontent.com/arrayfire/arrayfire-data/<commit>/matrixmarket/, checks it against the manifest, and restores it into the build tree. The tests are then on, and the CI configurations point their download at the restored files (.github/scripts/matrixmarket.cmake and the ci preset), so the configure downloads nothing. A failed download or check fails the build, naming the file.

To turn the tests on, set commit to a full commit SHA of arrayfire-data that has matrixmarket/. When the tests' list of matrices changes, update the manifest, matrixmarket.cmake and the ci preset together; check-matrix-data-test.py checks that they agree.

The manifest comes from ArrayFire's fix/restore-ci branch.