Add codecov step

Author: schwitanski

.github/workflows/ci.yml

@@ -19,39 +19,96 @@ jobs:
   build:
     runs-on: ${{ matrix.os }}
     strategy:
+      fail-fast: false
       matrix:
-        os: [ubuntu-22.04, ubuntu-24.04, macos-latest]
+        cmake_version: [4.0.1, 3.31.7, 3.28.6, 3.26.6, 3.21.7, 3.20.6, 3.16.9, 3.12.4, 3.10.3]
         compiler: [gcc, clang]
+        generator: [Ninja, Unix Makefiles]
+        os: [ubuntu-24.04]
+        # CMake-Codecov relies on compiling with absolute paths, but CMake uses absolute paths 
+        # with Ninja only starting with 3.21, so exclude older (non-supported) versions
         exclude:
-          - os: macos-latest
+          - cmake_version: 3.20.6
+            generator: Ninja
+          - cmake_version: 3.16.9
+            generator: Ninja
+          - cmake_version: 3.12.4
+            generator: Ninja
+          - cmake_version: 3.10.3
+            generator: Ninja
+        # Additionally test Ubuntu and macOS with default packages
+        include:
+          - os: ubuntu-22.04
+            cmake_version: default
+            generator: Unix Makefiles
+            compiler: gcc
+          - os: ubuntu-22.04
+            cmake_version: default
+            generator: Unix Makefiles
+            compiler: clang
+          - os: ubuntu-22.04
+            cmake_version: default
+            generator: Ninja
             compiler: gcc
-    
+          - os: ubuntu-22.04
+            cmake_version: default
+            generator: Ninja
+            compiler: clang
+          - os: macos-latest
+            compiler: clang
+            cmake_version: default
+            generator: Unix Makefiles
+          - os: macos-latest
+            compiler: clang
+            cmake_version: default
+            generator: Ninja
+
     steps:
       - name: Checkout code
         uses: actions/checkout@v4
 
-      - name: Install CMake, lcov, gfortran on Linux
+      - name: Install lcov, compilers on Linux
         if: runner.os == 'Linux'
         run: |
           sudo apt-get update
-          sudo apt-get install -y cmake lcov gfortran
+          sudo apt-get install -y lcov gfortran ${{ matrix.compiler }}
+
+      - name: Install default CMake
+        if: runner.os == 'Linux' && matrix.cmake_version == 'default'
+        run: |
+          sudo apt-get update
+          sudo apt-get install -y cmake
+
+      - name: Install specific CMake version
+        if: runner.os == 'Linux' && matrix.cmake_version != 'default'
+        run: |
+          sudo apt-get update
+          sudo apt-get install -y wget
+          wget https://github.com/Kitware/CMake/releases/download/v${{ matrix.cmake_version }}/cmake-${{ matrix.cmake_version }}-linux-x86_64.tar.gz
+          tar -xzf cmake-${{ matrix.cmake_version }}-linux-x86_64.tar.gz --strip-components=1 -C cmake
+          sudo cp -r cmake/* /usr/local/
       
       - name: Install CMake, lcov on macOS
         if: runner.os == 'macOS'
         run: |
           brew update
           brew install cmake lcov
 
+      - name: Print CMake version
+        run: cmake --version
+
       - name: Configure and build
         run: |
           mkdir build && cd build
-          cmake .. -DENABLE_COVERAGE=On
-          make
-          make gcov lcov test
-
-      - name: lcov report
-        uses: actions/upload-artifact@v4
-        with:
-          name: code-coverage-report
-          path: ./build/lcov
+          cmake .. -DCMAKE_C_COMPILER="${{ matrix.compiler }}" -G "${{ matrix.generator }}" -DENABLE_COVERAGE=On
+          cmake --build .
+          cmake --build . --target test
+          cmake --build . --target gcov
+          cmake --build . --target lcov
 
+      # - name: Codecov upload
+      #   uses: codecov/codecov-action@v5
+      #   with:
+      #     name: codecov-coverage
+      #     token: ${{ secrets.CODECOV_TOKEN }}
+      #     fail_ci_if_error: true