Add CI run to gather code coverage

Author: ianthomas23

.github/workflows/test.yml

@@ -47,3 +47,50 @@ jobs:
         run: |
           pytest -v
 
+  coverage:
+    name: 'Test coverage'
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout source
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+
+      - name: Create micromamba environment
+        uses: mamba-org/setup-micromamba@main
+        with:
+          environment-file: dev-environment.yml
+          cache-environment: true
+          create-args: lcov
+
+      - name: Configure CMake
+        run: |
+          cmake -Bbuild -DCMAKE_INSTALL_PREFIX=$CONDA_PREFIX -DCMAKE_BUILD_TYPE=Debug -DCMAKE_CXX_FLAGS_DEBUG="-g -O0 --coverage"
+
+      - name: Build with CMake
+        working-directory: build
+        run: cmake --build . --parallel 8
+
+      - name: Run tests
+        run: |
+          pytest -v
+
+      - name: Collect C++ coverage
+        run: |
+          lcov --version
+          lcov --output-file coverage.lcov --directory . --capture
+          lcov --output-file coverage.lcov --extract coverage.lcov '*/git2cpp/src/*'
+          genhtml coverage.lcov --output-directory outdir
+
+      - name: Upload artifact containing coverage report
+        uses: actions/upload-artifact@v6
+        with:
+          name: coverage_report
+          path: outdir
+
+      #- name: Upload coverage to codecov
+      #  uses: codecov/codecov-action@v5
+      #  with:
+      #    files: coverage.lcov
+      #    token: ${{ secrets.CODECOV_TOKEN }}
+      #    verbose: true