Merge pull request #183 from moonlandar/feat/cpp-testing-skill

Feat/cpp testing skill
2026-02-12 17:33:31 +08:00 · 2026-02-11 05:56:38 -08:00
parent 0278224b27 a5ec19cb8d
commit 3bc8672432
3 changed files with 324 additions and 0 deletions
--- a/README.md
+++ b/README.md
@@ -218,6 +218,7 @@ everything-claude-code/
 |   |-- verification-loop/          # Continuous verification (Longform Guide)
 |   |-- golang-patterns/            # Go idioms and best practices
 |   |-- golang-testing/             # Go testing patterns, TDD, benchmarks
+|   |-- cpp-testing/                # C++ testing with GoogleTest, CMake/CTest (NEW)
 |   |-- django-patterns/            # Django patterns, models, views (NEW)
 |   |-- django-security/            # Django security best practices (NEW)
 |   |-- django-tdd/                 # Django TDD workflow (NEW)
--- a/README.zh-CN.md
+++ b/README.zh-CN.md
@@ -171,6 +171,7 @@ everything-claude-code/
 |   |-- verification-loop/          # 持续验证（详细指南）
 |   |-- golang-patterns/            # Go 惯用语和最佳实践（新增）
 |   |-- golang-testing/             # Go 测试模式、TDD、基准测试（新增）
+|   |-- cpp-testing/                # C++ 测试模式、GoogleTest、CMake/CTest（新增）
 |
 |-- commands/         # 用于快速执行的斜杠命令
 |   |-- tdd.md              # /tdd - 测试驱动开发
--- a/skills/cpp-testing/SKILL.md
+++ b/skills/cpp-testing/SKILL.md
@@ -0,0 +1,322 @@
+---
+name: cpp-testing
+description: Use only when writing/updating/fixing C++ tests, configuring GoogleTest/CTest, diagnosing failing or flaky tests, or adding coverage/sanitizers.
+---
+
+# C++ Testing (Agent Skill)
+
+Agent-focused testing workflow for modern C++ (C++17/20) using GoogleTest/GoogleMock with CMake/CTest.
+
+## When to Use
+
+- Writing new C++ tests or fixing existing tests
+- Designing unit/integration test coverage for C++ components
+- Adding test coverage, CI gating, or regression protection
+- Configuring CMake/CTest workflows for consistent execution
+- Investigating test failures or flaky behavior
+- Enabling sanitizers for memory/race diagnostics
+
+### When NOT to Use
+
+- Implementing new product features without test changes
+- Large-scale refactors unrelated to test coverage or failures
+- Performance tuning without test regressions to validate
+- Non-C++ projects or non-test tasks
+
+## Core Concepts
+
+- **TDD loop**: red → green → refactor (tests first, minimal fix, then cleanups).
+- **Isolation**: prefer dependency injection and fakes over global state.
+- **Test layout**: `tests/unit`, `tests/integration`, `tests/testdata`.
+- **Mocks vs fakes**: mock for interactions, fake for stateful behavior.
+- **CTest discovery**: use `gtest_discover_tests()` for stable test discovery.
+- **CI signal**: run subset first, then full suite with `--output-on-failure`.
+
+## TDD Workflow
+
+Follow the RED → GREEN → REFACTOR loop:
+
+1. **RED**: write a failing test that captures the new behavior
+2. **GREEN**: implement the smallest change to pass
+3. **REFACTOR**: clean up while tests stay green
+
+```cpp
+// tests/add_test.cpp
+#include <gtest/gtest.h>
+
+int Add(int a, int b); // Provided by production code.
+
+TEST(AddTest, AddsTwoNumbers) { // RED
+  EXPECT_EQ(Add(2, 3), 5);
+}
+
+// src/add.cpp
+int Add(int a, int b) { // GREEN
+  return a + b;
+}
+
+// REFACTOR: simplify/rename once tests pass
+```
+
+## Code Examples
+
+### Basic Unit Test (gtest)
+
+```cpp
+// tests/calculator_test.cpp
+#include <gtest/gtest.h>
+
+int Add(int a, int b); // Provided by production code.
+
+TEST(CalculatorTest, AddsTwoNumbers) {
+    EXPECT_EQ(Add(2, 3), 5);
+}
+```
+
+### Fixture (gtest)
+
+```cpp
+// tests/user_store_test.cpp
+// Pseudocode stub: replace UserStore/User with project types.
+#include <gtest/gtest.h>
+#include <memory>
+#include <optional>
+#include <string>
+
+struct User { std::string name; };
+class UserStore {
+public:
+    explicit UserStore(std::string /*path*/) {}
+    void Seed(std::initializer_list<User> /*users*/) {}
+    std::optional<User> Find(const std::string &/*name*/) { return User{"alice"}; }
+};
+
+class UserStoreTest : public ::testing::Test {
+protected:
+    void SetUp() override {
+        store = std::make_unique<UserStore>(":memory:");
+        store->Seed({{"alice"}, {"bob"}});
+    }
+
+    std::unique_ptr<UserStore> store;
+};
+
+TEST_F(UserStoreTest, FindsExistingUser) {
+    auto user = store->Find("alice");
+    ASSERT_TRUE(user.has_value());
+    EXPECT_EQ(user->name, "alice");
+}
+```
+
+### Mock (gmock)
+
+```cpp
+// tests/notifier_test.cpp
+#include <gmock/gmock.h>
+#include <gtest/gtest.h>
+#include <string>
+
+class Notifier {
+public:
+    virtual ~Notifier() = default;
+    virtual void Send(const std::string &message) = 0;
+};
+
+class MockNotifier : public Notifier {
+public:
+    MOCK_METHOD(void, Send, (const std::string &message), (override));
+};
+
+class Service {
+public:
+    explicit Service(Notifier &notifier) : notifier_(notifier) {}
+    void Publish(const std::string &message) { notifier_.Send(message); }
+
+private:
+    Notifier &notifier_;
+};
+
+TEST(ServiceTest, SendsNotifications) {
+    MockNotifier notifier;
+    Service service(notifier);
+
+    EXPECT_CALL(notifier, Send("hello")).Times(1);
+    service.Publish("hello");
+}
+```
+
+### CMake/CTest Quickstart
+
+```cmake
+# CMakeLists.txt (excerpt)
+cmake_minimum_required(VERSION 3.20)
+project(example LANGUAGES CXX)
+
+set(CMAKE_CXX_STANDARD 20)
+set(CMAKE_CXX_STANDARD_REQUIRED ON)
+
+include(FetchContent)
+# Prefer project-locked versions. If using a tag, use a pinned version per project policy.
+set(GTEST_VERSION v1.17.0) # Adjust to project policy.
+FetchContent_Declare(
+  googletest
+  URL https://github.com/google/googletest/archive/refs/tags/${GTEST_VERSION}.zip
+)
+FetchContent_MakeAvailable(googletest)
+
+add_executable(example_tests
+  tests/calculator_test.cpp
+  src/calculator.cpp
+)
+target_link_libraries(example_tests GTest::gtest GTest::gmock GTest::gtest_main)
+
+enable_testing()
+include(GoogleTest)
+gtest_discover_tests(example_tests)
+```
+
+```bash
+cmake -S . -B build -DCMAKE_BUILD_TYPE=Debug
+cmake --build build -j
+ctest --test-dir build --output-on-failure
+```
+
+## Running Tests
+
+```bash
+ctest --test-dir build --output-on-failure
+ctest --test-dir build -R ClampTest
+ctest --test-dir build -R "UserStoreTest.*" --output-on-failure
+```
+
+```bash
+./build/example_tests --gtest_filter=ClampTest.*
+./build/example_tests --gtest_filter=UserStoreTest.FindsExistingUser
+```
+
+## Debugging Failures
+
+1. Re-run the single failing test with gtest filter.
+2. Add scoped logging around the failing assertion.
+3. Re-run with sanitizers enabled.
+4. Expand to full suite once the root cause is fixed.
+
+## Coverage
+
+Prefer target-level settings instead of global flags.
+
+```cmake
+option(ENABLE_COVERAGE "Enable coverage flags" OFF)
+
+if(ENABLE_COVERAGE)
+  if(CMAKE_CXX_COMPILER_ID MATCHES "GNU")
+    target_compile_options(example_tests PRIVATE --coverage)
+    target_link_options(example_tests PRIVATE --coverage)
+  elseif(CMAKE_CXX_COMPILER_ID MATCHES "Clang")
+    target_compile_options(example_tests PRIVATE -fprofile-instr-generate -fcoverage-mapping)
+    target_link_options(example_tests PRIVATE -fprofile-instr-generate)
+  endif()
+endif()
+```
+
+GCC + gcov + lcov:
+
+```bash
+cmake -S . -B build-cov -DENABLE_COVERAGE=ON
+cmake --build build-cov -j
+ctest --test-dir build-cov
+lcov --capture --directory build-cov --output-file coverage.info
+lcov --remove coverage.info '/usr/*' --output-file coverage.info
+genhtml coverage.info --output-directory coverage
+```
+
+Clang + llvm-cov:
+
+```bash
+cmake -S . -B build-llvm -DENABLE_COVERAGE=ON -DCMAKE_CXX_COMPILER=clang++
+cmake --build build-llvm -j
+LLVM_PROFILE_FILE="build-llvm/default.profraw" ctest --test-dir build-llvm
+llvm-profdata merge -sparse build-llvm/default.profraw -o build-llvm/default.profdata
+llvm-cov report build-llvm/example_tests -instr-profile=build-llvm/default.profdata
+```
+
+## Sanitizers
+
+```cmake
+option(ENABLE_ASAN "Enable AddressSanitizer" OFF)
+option(ENABLE_UBSAN "Enable UndefinedBehaviorSanitizer" OFF)
+option(ENABLE_TSAN "Enable ThreadSanitizer" OFF)
+
+if(ENABLE_ASAN)
+  add_compile_options(-fsanitize=address -fno-omit-frame-pointer)
+  add_link_options(-fsanitize=address)
+endif()
+if(ENABLE_UBSAN)
+  add_compile_options(-fsanitize=undefined -fno-omit-frame-pointer)
+  add_link_options(-fsanitize=undefined)
+endif()
+if(ENABLE_TSAN)
+  add_compile_options(-fsanitize=thread)
+  add_link_options(-fsanitize=thread)
+endif()
+```
+
+## Flaky Tests Guardrails
+
+- Never use `sleep` for synchronization; use condition variables or latches.
+- Make temp directories unique per test and always clean them.
+- Avoid real time, network, or filesystem dependencies in unit tests.
+- Use deterministic seeds for randomized inputs.
+
+## Best Practices
+
+### DO
+
+- Keep tests deterministic and isolated
+- Prefer dependency injection over globals
+- Use `ASSERT_*` for preconditions, `EXPECT_*` for multiple checks
+- Separate unit vs integration tests in CTest labels or directories
+- Run sanitizers in CI for memory and race detection
+
+### DON'T
+
+- Don't depend on real time or network in unit tests
+- Don't use sleeps as synchronization when a condition variable can be used
+- Don't over-mock simple value objects
+- Don't use brittle string matching for non-critical logs
+
+### Common Pitfalls
+
+- **Using fixed temp paths** → Generate unique temp directories per test and clean them.
+- **Relying on wall clock time** → Inject a clock or use fake time sources.
+- **Flaky concurrency tests** → Use condition variables/latches and bounded waits.
+- **Hidden global state** → Reset global state in fixtures or remove globals.
+- **Over-mocking** → Prefer fakes for stateful behavior and only mock interactions.
+- **Missing sanitizer runs** → Add ASan/UBSan/TSan builds in CI.
+- **Coverage on debug-only builds** → Ensure coverage targets use consistent flags.
+
+## Optional Appendix: Fuzzing / Property Testing
+
+Only use if the project already supports LLVM/libFuzzer or a property-testing library.
+
+- **libFuzzer**: best for pure functions with minimal I/O.
+- **RapidCheck**: property-based tests to validate invariants.
+
+Minimal libFuzzer harness (pseudocode: replace ParseConfig):
+
+```cpp
+#include <cstddef>
+#include <cstdint>
+#include <string>
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
+    std::string input(reinterpret_cast<const char *>(data), size);
+    // ParseConfig(input); // project function
+    return 0;
+}
+```
+
+## Alternatives to GoogleTest
+
+- **Catch2**: header-only, expressive matchers
+- **doctest**: lightweight, minimal compile overhead