added code coverage test into linux gcc workflow

.github/workflows/linux.yml

@@ -30,6 +30,7 @@ jobs:
           - os: ubuntu-latest
             c_compiler: gcc
             cpp_compiler: g++
+            build_type: Coverage
           - os: ubuntu-latest
             c_compiler: clang
             cpp_compiler: clang++
@@ -65,3 +66,11 @@ jobs:
       # Execute tests defined by the CMake configuration. Note that --build-config is needed because the default Windows generator is a multi-config generator (Visual Studio generator).
       # See https://cmake.org/cmake/help/latest/manual/ctest.1.html for more detail
       run: ctest --build-config ${{ matrix.build_type }}
+
+    - name: Code Coverage
+      if: matrix.c_compiler == 'gcc'
+      working-directory: ${{ steps.strings.outputs.build-output-dir }}
+      run: |
+        sudo apt-get update
+        sudo apt-get install -y gcovr
+        gcovr -r .. -f ../src

CMakeLists.txt

@@ -56,4 +56,13 @@ target_include_directories(${PROJECT_NAME}-tests
 list(APPEND CMAKE_MODULE_PATH "${PROJECT_SOURCE_DIR}/dependencies/doctest/scripts/cmake")
 include(doctest)
 
-doctest_discover_tests(${PROJECT_NAME}-tests)
+doctest_discover_tests(${PROJECT_NAME}-tests)
+
+
+# ========================================
+# Code Coverage
+# ========================================
+if (CMAKE_BUILD_TYPE STREQUAL "Coverage")
+    SET(CMAKE_CXX_FLAGS "-g -O0 --coverage")
+    SET(CMAKE_C_FLAGS "-g -O0 --coverage")
+endif ()