[CI] Add code coverage testing

Author: PetroZarytskyi

.codecov.yml

@@ -0,0 +1,38 @@
+codecov:
+  require_ci_to_pass: no
+
+coverage:
+  precision: 2
+  round: down
+  range: "5...100"
+
+  status:
+    project:
+      default:
+        target: auto # will use the coverage from the base commit
+        threshold: 2 # Allow to drop by 2%, and posting a success status.
+    patch:
+      default:
+        target: 98 # Force 98% coverage with 2% threshold.
+        threshold: 2 # Allow to drop by 2%, and posting a success status.
+    changes: no
+
+parsers:
+  gcov:
+    branch_detection:
+      conditional: yes
+      loop: yes
+      method: yes
+      macro: no
+
+comment:
+  layout: "reach, diff, flags, tree, files"
+  behavior: default
+  require_changes: no
+
+ignore:
+  - test/*
+  - test/**/*
+
+github_checks:
+  annotations: true # Deprecated but very useful

.github/workflows/cvmfs-ci.yml

@@ -40,6 +40,7 @@ jobs:
           - LCG_RELEASE: "LCG_108"
             LCG_ARCH: "x86_64-ubuntu2204-gcc11-opt"
             ROOT: "6.36.02"
+            coverage: true
           - LCG_RELEASE: "dev3/latest"
             LCG_ARCH: "x86_64-ubuntu2204-gcc11-opt"
             ROOT: "LCG master"
@@ -56,6 +57,23 @@ jobs:
         with:
           cvmfs_repositories: ${{ (env.CMSSW_VERSION != '') && 'cms.cern.ch' || 'sft.cern.ch' }}
 
+      - name: Setup compiler
+        run: |
+          echo "CC=$(which gcc)" >> $GITHUB_ENV
+          echo "CXX=$(which g++)" >> $GITHUB_ENV
+
+      - name: Setup code coverage
+        if: ${{ (matrix.coverage == true) }}
+        run: |
+          sudo apt install -y lcov
+          # Workaround ubuntu lcov-1.15-1 package bug
+          if sudo apt list lcov --installed | grep "1.15-1" ; then
+            wget https://launchpad.net/ubuntu/+source/lcov/1.15-2/+build/23784466/+files/lcov_1.15-2_all.deb
+            sudo apt install -y ./lcov_1.15-2_all.deb
+          fi
+          echo "COMBINE_CODE_COVERAGE=1" >> $GITHUB_ENV
+          echo "BUILD_TYPE=Debug" >> $GITHUB_ENV
+
       - name: Build Combine (LCG)
         if: ${{ env.CMSSW_VERSION == '' }}
         env:
@@ -70,7 +88,8 @@ jobs:
           mkdir build;
           cd build;
           cmake -DCMAKE_INSTALL_PREFIX=../install \
-                -DCMAKE_BUILD_TYPE=RelWithDebInfo \
+                -DCMAKE_BUILD_TYPE=$([[ -z "$BUILD_TYPE" ]] && echo RelWithDebInfo || echo $BUILD_TYPE) \
+                -DCOMBINE_CODE_COVERAGE=${{ env.COMBINE_CODE_COVERAGE }} \
                 -DUSE_VDT=${USE_VDT} \
                 -DBUILD_TESTS=TRUE \
                 ..;
@@ -245,3 +264,28 @@ jobs:
           script: |
             cd test
             python3 test_interference.py
+
+      - name: Prepare code coverage report
+        if: ${{ success() && (matrix.coverage == true) }}
+        run: |
+          # Create lcov report
+          # capture coverage info
+          lcov --directory . --capture --output-file coverage.info --gcov-tool $CONDA_PREFIX/bin/gcov --ignore-errors gcov
+          # filter out system and extra files.
+          # To also not include test code in coverage add them with full path to the patterns: '*/ci/*'
+          lcov --remove coverage.info \
+            '/usr/*' \
+            "${HOME}/.cache/*" \
+            '*/ci/*' \
+            --output-file coverage.info
+          # output coverage data for debugging (optional)
+          lcov --list coverage.info
+
+      - name: Upload to codecov.io
+        if: ${{ success() && (matrix.coverage == true) }}
+        uses: codecov/codecov-action@v5
+        with:
+          files: ./coverage.info
+          fail_ci_if_error: true
+          verbose: true
+          token: ${{ secrets.CODECOV_TOKEN }}

CMakeLists.txt

@@ -53,6 +53,21 @@ set(LIBNAME HiggsAnalysisCombinedLimit)
 
 set(CMAKE_LIBRARY_OUTPUT_DIRECTORY "lib")
 
+## Code Coverage Configuration
+option(COMBINE_CODE_COVERAGE "Enable coverage reporting" OFF)
+if(COMBINE_CODE_COVERAGE AND CMAKE_CXX_COMPILER_ID MATCHES "GNU|Clang")
+  string(TOUPPER "${CMAKE_BUILD_TYPE}" uppercase_CMAKE_BUILD_TYPE)
+  if(NOT uppercase_CMAKE_BUILD_TYPE STREQUAL "DEBUG")
+    message(FATAL_ERROR "CodeCov enabled on non-debug build!")
+  endif()
+  set(GCC_COVERAGE_COMPILE_FLAGS "-fprofile-arcs -ftest-coverage")
+  set(GCC_COVERAGE_LINK_FLAGS    "--coverage")
+  set(CMAKE_CXX_FLAGS            "${CMAKE_CXX_FLAGS} ${GCC_COVERAGE_COMPILE_FLAGS}")
+  set(CMAKE_SHARED_LIBRARY_CREATE_CXX_FLAGS "${CMAKE_SHARED_LIBRARY_CREATE_CXX_FLAGS} ${GCC_COVERAGE_COMPILE_FLAGS}")
+  set(CMAKE_EXE_LINKER_FLAGS     "${CMAKE_EXE_LINKER_FLAGS} ${GCC_COVERAGE_LINK_FLAGS}")
+  set(CMAKE_SHARED_LINKER_FLAGS  "${CMAKE_SHARED_LINKER_FLAGS} ${GCC_COVERAGE_LINK_FLAGS}")
+endif()
+
 file(GLOB HEADERS RELATIVE ${CMAKE_CURRENT_SOURCE_DIR} interface/*.h*)
 file(GLOB SOURCES RELATIVE ${CMAKE_CURRENT_SOURCE_DIR} src/*.c*)