cpp-testing

Use FetchContent to pull a pinned googletest release, link your test executable against GTest::gtest, GTest::gmock, and GTest::gtest_main, then call gtest_discover_tests after enable_testing. Run tests with ctest --test-dir build --output-on-failure.

Run the test binary directly with --gtest_filter, for example ./build/example_tests --gtest_filter=UserStoreTest.FindsExistingUser. Alternatively use ctest with -R and a regex matching the test name.

GoogleTest with GoogleMock provides full mocking and broad CTest integration. Catch2 is header-only with expressive matchers, and doctest offers minimal compile overhead. Choose based on mocking needs and build-time constraints.

For GCC, compile and link with --coverage, then capture results with lcov and render HTML via genhtml. For Clang, use -fprofile-instr-generate -fcoverage-mapping and report with llvm-profdata and llvm-cov.

Flakiness usually comes from sleeps used for synchronization, wall-clock time dependencies, shared temp paths, or hidden global state. Replace sleeps with condition variables or latches, inject clocks, use unique temp directories, and reset state in fixtures.

Enable AddressSanitizer for memory errors, UndefinedBehaviorSanitizer for undefined behavior, and ThreadSanitizer for data races, typically as dedicated CI build configurations. Add the corresponding -fsanitize flags to both compile and link options.