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 enable_testing() and gtest_discover_tests() so CTest discovers each test case automatically.

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

Use GoogleMock mocks when verifying interactions, such as expecting a method call with specific arguments. Use fakes when you need stateful behavior, like an in-memory store, and prefer dependency injection over global state for testability.

For GCC, add --coverage to compile and link options, 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 sleep-based synchronization, shared temp directories, real time or network dependencies, and nondeterministic randomness. Use condition variables or latches, unique temp directories per test, and deterministic seeds.

Enable ASan when investigating memory errors like use-after-free or buffer overflows, and TSan when diagnosing data races in multithreaded code. Add the corresponding -fsanitize flags to compile and link options, then re-run the failing test.