C++ Code Coverage

Steps

• Clean project completely (you want a complete rebuild)
• Recompile everything with gcov compile and link flags.
• Use lcov to process initial .gcno files.
• Run all tests.
• Use lcov to process .gcna coverage files.
• Merge the initial and final lcov files (step 3 and step 5).
• Filter lcov output to only include project files.
• Filter lcov output to exclude unit test files, and main.cpp
• Generate html coverage report from final filtered lcov output.

CMakeLists.txt

WORKING_DIRECTORY ${CMAKE_BINARY_DIR}

# Code coverage results with an optimised (non-Debug) build may be misleading
CMAKE_CXX_FLAGS "-g -O0 -Wall -fprofile-arcs -ftest-coverage"
CMAKE_C_FLAGS "-g -O0 -Wall -W -fprofile-arcs -ftest-coverage")

LINK_LIBRARIES(gcov)

Compile_options

-fprofile-arcs
-ftest-coverage

Link_options

--coverage

Notes

• Run test, generating the corresponding .gcda files.
• In the directory in which files .gcno and .gcda are located do the following: ``` lcov -c -d . -o name.info

lcov –directory . –capture –output-file name.info lcov –remove name.info ‘tests/’ ‘/usr/’ –output-file name.info.cleaned

* Generate the HTML report

genhtml name.info genhtml -o out name.info –ignore-errors source

genhtml -o name name.info.cleaned cmake -E remove name.info name.info.cleaned ```

Links:

• https://github.com/cmake-modules/lcov/blob/master/coverage.cmake
• C++ using GCOV/LCOV in a CMake project – Stack Overflow
• Line coverage report using gcov/lcov
• https://github.com/britram/libfc/blob/master/CodeCoverage.cmake
• Use gcov and lcov to know your test coverage
• C# example
• Github action
• C++ example