ci: Add basic nogil operator tests

Author: enwask

.github/workflows/pytest-core-nompi.yml

@@ -39,6 +39,7 @@ jobs:
            pytest-osx-py312-clang-omp,
            pytest-docker-py310-gcc-omp,
            pytest-docker-py310-icx-omp,
+           pytest-docker-py313-gcc-nogil,
            pytest-ubuntu-py313-gcc14-omp
         ]
         set: [base, adjoint]
@@ -95,29 +96,46 @@ jobs:
         - name: pytest-docker-py310-gcc-omp
           python-version: '3.10'
           os: ubuntu-latest
+          base-image: "cpu-gcc"
           arch: "gcc"
           language: "openmp"
           sympy: "1.13"
 
         - name: pytest-docker-py310-icx-omp
           python-version: '3.10'
           os: ubuntu-latest
+          base-image: "cpu-icx"
           arch: "icx"
           language: "openmp"
           sympy: "1.13"
 
+        - name: pytest-docker-py313-gcc-nogil
+          python-version: '3.13'
+          os: ubuntu-latest
+          base-image: "cpu-gcc-nogil"
+          arch: "gcc"
+          language: "C"
+          sympy: "1.14"
+
         - name: pytest-ubuntu-py313-gcc14-omp
           python-version: '3.13'
           os: ubuntu-24.04
           arch: "gcc-14"
           language: "openmp"
           sympy: "1.14"
+          set: operator
 
         - set: base
           test-set: 'not adjoint'
+          test-path: 'tests/'
 
         - set: adjoint
           test-set: 'adjoint'
+          test-path: 'tests/'
+
+        - set: operator
+          test-set: ''
+          test-path: 'tests/test_operator.py'
 
         exclude:
         - name: pytest-osx-py312-clang-omp
@@ -137,7 +155,7 @@ jobs:
     - name: Build docker image
       if: contains(matrix.name, 'docker')
       run: |
-          docker build . --file docker/Dockerfile.devito --tag devito_img --build-arg base=devitocodes/bases:cpu-${{ matrix.arch }}
+          docker build . --file docker/Dockerfile.devito --tag devito_img --build-arg base=devitocodes/bases:${{ matrix.base-image }}
 
     - name: Set run prefix
       run: |
@@ -195,7 +213,7 @@ jobs:
 
     - name: Test with pytest
       run: |
-        ${{ env.RUN_CMD }} pytest -k "${{ matrix.test-set }}" -m "not parallel" --cov --cov-config=.coveragerc --cov-report=xml tests/
+        ${{ env.RUN_CMD }} pytest -k "${{ matrix.test-set }}" -m "not parallel" --cov --cov-config=.coveragerc --cov-report=xml "${{ matrix.test-path }}"
 
     - name: Upload coverage to Codecov
       if: "!contains(matrix.name, 'docker')"