Unit test coverage

CONTRIBUTING.md

@@ -1,3 +1,4 @@
+
 # SplashKit Development
 
 ## macOS
@@ -20,31 +21,79 @@
    git clone --recursive -j2 https://github.com/<username>/splashkit-core.git
    ```
 
-3. Build the test project:
+3. Initialise submodules if they weren't included during clone:
 
-   - In a terminal application, go into the cloned directory of your SplashKit
-     fork, and type:
+   ```sh
+   git submodule update --init --recursive
+   ```
+
+4. Build the test project:
+
+   - In a terminal application, go into the cloned directory of your SplashKit fork, and type:
 
      ```sh
      cd projects/cmake
      cmake .
      make
      ```
 
-4. Run the test program by executing
+   - For Apple Silicon (arm64) Macs, you may need to specify the architecture:
+
+     ```sh
+     cd projects/cmake
+     # Clean any previous build files if you encounter errors
+     ./clean.sh
+     cmake . -DCMAKE_OSX_ARCHITECTURES=arm64
+     make
+     ```
+
+5. Run the test program by executing:
 
    ```sh
    cd ../../bin
    ./sktest
    ```
 
-5. Add features to code in
+6. Generate Code Coverage Report (requires lcov)
+
+   SplashKit includes a CMake preset for generating code coverage reports using lcov. To use it:
+
+   ```sh
+   # Install lcov if you don't have it
+   brew install lcov
+
+   # Navigate to the cmake directory from the repository root
+   cd projects/cmake
+
+   # Configure the project with coverage flags
+   cmake --preset macOSCoverage -S .
+
+   # Build the project
+   cmake --build --preset macOSCoverage
+
+   # Run the tests to generate coverage data
+   cd ../../bin && ./skunit_tests
+
+   # Generate the coverage report
+   cd ..
+   lcov --capture --directory projects/cmake/build/macOSCoverage --output-file coverage.info --ignore-errors inconsistent,unsupported,format,count --include "/coresdk/src/coresdk/" --include "/coresdk/src/backend/"
+
+   # Create an HTML report
+   genhtml coverage.info --output-directory coverage_report --ignore-errors inconsistent,corrupt,unsupported,category
+
+   # Open the report
+   open coverage_report/index.html
+   ```
+
+   The report will show which parts of your code are covered by tests and which parts are not covered. This helps identify areas that need additional testing.
+
+7. Add features to code in:
 
    ```sh
    ./coresdk
    ```
 
-6. Add test code into `coresdk/src/test`. Now you should be good to go.
+8. Add test code into `coresdk/src/test`. Now you should be good to go.
 
 ## Linux
 

projects/cmake/CMakeLists.txt

@@ -17,6 +17,13 @@ set(SK_BIN "${CMAKE_CURRENT_SOURCE_DIR}/../../bin")
 # FLAGS
 set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++20")
 
+# Option to use GCOV for coverage when compiling and linking
+option(USE_COVERAGE "Enable coverage during the build" OFF)
+if(USE_COVERAGE)
+    add_compile_options(--coverage)
+    add_link_options(--coverage)
+endif()
+
 # Includes for CTest/Catch2 integration
 include(CTest)
 include("${CMAKE_CURRENT_SOURCE_DIR}/catch/Catch.cmake")
@@ -325,4 +332,58 @@ catch_discover_tests(skunit_tests)
 #### END sktest EXECUTABLE ####
 
 install(TARGETS SplashKitBackend DESTINATION lib)
-install(FILES ${INCLUDE_FILES} DESTINATION include/SplashKitBackend)
+install(FILES ${INCLUDE_FILES} DESTINATION include/SplashKitBackend)
+
+# Coverage collection with LCOV
+# Get absolute path to SK_SRC so we can pass it to LCOV
+# and collect coverage only for src files
+get_filename_component(SRC_ABS ${SK_SRC} ABSOLUTE)
+message(SRC_ABS="${SRC_ABS}")
+
+if(USE_COVERAGE)
+    if(APPLE OR MSYS)
+        find_program(GCOVR gcovr REQUIRED)
+    else()
+        find_program(LCOV lcov REQUIRED)
+        set(LCOV_BASE lcov-base.info)
+        set(LCOV_TEST lcov-test.info)
+        set(LCOV_LOG lcov.log)
+        set(LCOV_ERR lcov.err)
+    endif()
+    set(LCOV_TOTAL lcov.info)
+endif()
+
+# lcov coverage targets
+# Collect baseline coverage before running tests
+add_custom_target(lcov-init-coverage
+    COMMENT "Collecting initial coverage with lcov"
+    COMMAND lcov --capture --initial --directory ${CMAKE_CURRENT_BINARY_DIR} --include "'${SRC_ABS}*'"
+        --output-file ${LCOV_BASE} 2>${LCOV_ERR} >${LCOV_LOG}
+)
+add_dependencies(lcov-init-coverage lcov-reset-coverage)
+
+add_custom_target(lcov-reset-coverage
+    COMMENT "Reset all coverage counters to zero with lcov"
+    COMMAND lcov --quiet --zerocounters --directory ${CMAKE_CURRENT_BINARY_DIR}
+        --output-file ${LCOV_BASE}
+    COMMAND lcov --quiet --zerocounters --directory ${CMAKE_CURRENT_BINARY_DIR}
+        --output-file ${LCOV_TEST}
+    COMMAND lcov --quiet --zerocounters --directory ${CMAKE_CURRENT_BINARY_DIR}
+        --output-file ${LCOV_TOTAL}
+)
+
+# Collect post-test coverage data
+add_custom_target(lcov-capture-coverage
+    COMMENT "Capture coverage data with lcov"
+    DEPENDS ${LCOV_BASE}
+    COMMAND lcov --capture --directory ${CMAKE_CURRENT_BINARY_DIR} --output-file ${LCOV_TEST} --include "'${SRC_ABS}*'"
+        2>${LCOV_ERR} >${LCOV_LOG}
+    COMMAND lcov --add-tracefile ${LCOV_BASE} --add-tracefile ${LCOV_TEST} --output-file ${LCOV_TOTAL}
+        >>${LCOV_LOG}
+)
+
+# gcovr post-test coverage target
+add_custom_target(gcovr-capture-coverage
+    COMMENT "Capture coverage data with gcovr"
+    COMMAND gcovr --root ../../.. --lcov ${LCOV_TOTAL} --filter ".*/coresdk/src/.*"
+)

projects/cmake/CMakePresets.json

@@ -9,7 +9,17 @@
             "cacheVariables": {
                 "CMAKE_C_COMPILER": "gcc",
                 "CMAKE_CXX_COMPILER": "g++",
-                "CMAKE_BUILD_TYPE": "Debug"
+                "CMAKE_BUILD_TYPE": "Debug",
+                "USE_COVERAGE": "OFF"
+            }
+        },
+        {
+            "name": "LinuxCoverage",
+            "displayName": "Linux with coverage",
+            "description": "Linux gcc g++",
+            "inherits": "Linux",
+            "cacheVariables": {
+                "USE_COVERAGE": "ON"
             }
         },
         {
@@ -33,7 +43,17 @@
             "cacheVariables": {
                 "CMAKE_C_COMPILER": "clang",
                 "CMAKE_CXX_COMPILER": "clang++",
-                "CMAKE_BUILD_TYPE": "Debug"
+                "CMAKE_BUILD_TYPE": "Debug",
+                "USE_COVERAGE": "OFF"
+            }
+        },
+        {
+            "name": "macOSCoverage",
+            "displayName": "macOS with coverage",
+            "description": "macOS clang",
+            "inherits": "macOS",
+            "cacheVariables": {
+                "USE_COVERAGE": "ON"
             }
         }
     ]