cpp-testing

name	cpp-testing
description	C++ testing workflow for unit and integration tests: GoogleTest/GoogleMock, CMake/CTest integration, diagnosing flaky tests, and running sanitizers and coverage for correctness signal. Use when writing or fixing C++ tests and test infrastructure.
license	MIT
compatibility	C++20 baseline. Tools: CMake 3.20+, CTest. Recommended: GoogleTest. Debugging: gdb/lldb/Valgrind (Linux/macOS), MinGW gdb + objdump (Windows), MSVC dumpbin + WinDbg (Windows). Optional: sanitizers (Clang/GCC/MSVC), coverage (llvm-cov or lcov).
metadata	{"author":"AeonDave","version":"1.1"}

C++ Testing

High-signal workflow for writing and maintaining reliable C++ tests.

When to activate

• Adding new unit tests, regression tests, or integration tests
• Fixing failing or flaky C++ tests
• Wiring GoogleTest with CMake/CTest
• Enabling sanitizers for memory/UB/race diagnostics

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Outcome expectations

• Fast deterministic unit tests with clear failure messages.
• Integration tests separated and labeled by cost/risk.
• Flake triage follows reproducible, root-cause-first workflow.
• Sanitizers/coverage are integrated as recurring quality signal.

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Core rules

• Tests must be deterministic: no sleeping for synchronization.
• Prefer fakes for state, mocks for interactions.
• Use ASSERT_* for preconditions, EXPECT_* for additional checks.
• Keep unit tests fast; label integration tests separately.
• Keep one source of truth for test configuration in CMake targets.
• Avoid production-only test hooks unless they expose a real design seam.
• Pair with test-driven-development when implementing persistent code or bug fixes test-first.
• Pair with testing-reliability for mock/timing anti-patterns and systematic-debugging when symptoms are far from the defect.

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Recommended workflow

1. Define the behavior and test scope (unit vs integration) first.
2. Add/adjust tests with clear Arrange-Act-Assert structure.
3. Run focused test selection (ctest -R / gtest filter).
4. Run sanitizers for memory/UB/races where applicable.
5. If flaky/failing, minimize reproducer and fix root cause before broad reruns.

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Triage loop for failing tests

1. Reproduce deterministically on one test binary.
2. Capture failure class: assertion mismatch, crash, timeout, data race, UB.
3. Narrow input/state until minimal failing case is obtained.
4. Fix production code first (or fixture isolation), then harden test.
5. Re-run focused + full suite + sanitizer build.

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Resources

Load on demand:

• references/googletest-cmake.md — FetchContent + CTest discovery (gtest_discover_tests)
• references/test-design.md — unit vs integration, fixtures, parameterized tests
• references/sanitizers-coverage.md — ASan/UBSan/TSan + coverage recipes
• references/flakes-debugging.md — anti-flake rules, gdb/lldb, Valgrind, MinGW objdump/nm, MSVC dumpbin/WinDbg, sanitizer env vars