[DROP BEFORE MERGE] Limit firedrake-check to a single GPU test and run nprocs=1 Firedrake tests on GPU CI

Author: dsroberts

.github/workflows/core.yml

@@ -491,7 +491,7 @@ jobs:
       PYOP2_CFLAGS: -fno-fast-math
       # NOTE: One should occasionally update test_durations.json by running
       # 'make test_durations' inside a 'firedrake:latest' Docker image.
-      EXTRA_PYTEST_ARGS: --splitting-algorithm least_duration --timeout=600 --timeout-method=thread -o faulthandler_timeout=660 --durations-path=./firedrake-repo/tests/test_durations.json --durations=50
+      EXTRA_PYTEST_ARGS: -m skipslepc --splitting-algorithm least_duration --timeout=600 --timeout-method=thread -o faulthandler_timeout=660 --durations-path=./firedrake-repo/tests/test_durations.json --durations=50
       PYTEST_MPI_MAX_NPROCS: 8
       # Prevent PETSc from exiting with an error due to using non-GPU aware system MPI
       PETSC_OPTIONS: -use_gpu_aware_mpi 0
@@ -588,7 +588,8 @@ jobs:
 
           pip install --verbose $EXTRA_PIP_FLAGS \
             --no-binary h5py \
-            './firedrake-repo[check]'
+            --extra-index-url https://download.pytorch.org/whl/cu130 \
+            './firedrake-repo[ci]'
 
           firedrake-clean
           pip list
@@ -622,6 +623,15 @@ jobs:
           echo "SNESSolve not found in PETSc log_view output!"
           exit 1
 
+      - name: Run Firedrake tests (nprocs = 1)
+        if: inputs.run_tests && (success() || steps.install.conclusion == 'success')
+        run: |
+          . venv/bin/activate
+          : # Use pytest-xdist here so we can have a single collated output (not possible
+          : # for parallel tests)
+          firedrake-run-split-tests 1 1 -n 8 "$EXTRA_PYTEST_ARGS" firedrake-repo/tests/firedrake
+        timeout-minutes: 90
+
       - name: Post-run cleanup
         if: always()
         run: |

scripts/firedrake-check

@@ -24,7 +24,7 @@ TESTS = {
         # near nullspace
         "tests/firedrake/regression/test_nullspace.py::test_near_nullspace",
         # GPU offload
-        "tests/firedrake/offload/test_poisson_offloading_pc.py::test_poisson_offload",
+        "tests/firedrake/offload/test_poisson_offloading_pc.py::test_poisson_offload[cg-gamg-True]",
     ),
     2: (
         # HDF5/checkpointing