Add note about : as separator in CSCS CI pipeline variables to CI reminder

[msimberg]

Also adds an empty line that was missing after a list.

[github-actions]

When developing, you can test your changes on CSCS CI before merge with the default pipeline: cscs-ci run default. This will run a default subset of tests.

You can pass options to override pipeline variables, for example:

• cscs-ci run default;BACKENDS=gtfn_cpu;LEVELS=unit
• cscs-ci run default;MODEL_SUBPACKAGES=common:driver;SESSIONS=model
  Avoid running the pipeline for all tests when you are developing.

Available options are:

• SESSIONS: model, model_mpi, or tools (correspond to nox sessions)
• MODEL_SUBSETS: datatest, basic, or stencils (correspond to nox session selections)
• MODEL_SUBPACKAGES: subpackages for non-MPI tests (last component, e.g. diffusion, driver)
• MODEL_MPI_SUBPACKAGES: subpackages for MPI tests (as above)
• BACKENDS: backends
• GRIDS: grids for stencil tests (simple, icon_regional, or icon_global)
• LEVELS: testing level for non-stencil tests (unit or integration)

For each option, all can be used as a shorthand for all possible values of that variable, e.g. LEVELS=all.

See scripts/python/generate_ci_pipeline.py and noxfile.py for available values for each option.

The all pipeline can be run with cscs-ci run all. This will run all icon4py tests in CSCS CI which can be expensive. This pipeline runs on a schedule on main, and can be run when extensive validation is needed (e.g. before releases).

Merging

Once your PR is approved and ready for merging, add it to the merge queue. The merge CSCS CI pipeline will run automatically on the merge-queue branch and must pass before the PR is merged. A dummy merge check will be triggered on the PR itself since it's required to add a PR to the merge queue.

Optional Tests

To run benchmarks you can use:

• cscs-ci run benchmark-bencher

For more detailed information please look at CI in the EXCLAIM universe.

[starkphi]

Looking good. Didn't know we could also list multiple pipelines in the same command, so I think it's a very helpful additional line.