attempt coverage

.github/workflows/main.yml

@@ -8,7 +8,9 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        python-version: ["3.9", "3.10", "3.11", "3.12"]
+        python-version: ["3.12"]
+        # XXX temporary to cut down on runs
+        # python-version: ["3.9", "3.10", "3.11", "3.12"]
 
     steps:
       - uses: actions/checkout@v4
@@ -22,9 +24,9 @@ jobs:
       - name: Install dependencies
         run: |
           python -m pip install --upgrade pip
-          pip install pytest
+          pip install pytest pytest-cov
       - name: Test with pytest
-        run: pytest tests --doctest-modules --junitxml=junit/test-results-${{ matrix.python-version }}.xml
+        run: pytest tests --cov --doctest-modules --junitxml=junit/test-results-${{ matrix.python-version }}.xml
       - name: Upload pytest test results
         uses: actions/upload-artifact@v4
         with: