cpp-unit-testing

This repo’s unit tests: - Use GoogleTest (`TEST`, `TEST_F`, etc.). - Live close to the code they cover in a `tests/` subdirectory. - Are registered with CTest via the CMake macro `smith_add_tests(...)`. ## Where tests go Place unit tests next to the component they cover: - `src/smith/<component>/tests/` (recommended for library code) - `src/tests/` (project-wide smoke/regression tests) Each `tests/` directory should contain: - One or more `*.cpp` test files - A `CMakeLists.txt` that registers those tests with `smith_add_tests` Also ensure the parent component adds the tests subdirectory when tests are enabled: ```cmake if(SMITH_ENABLE_TESTS) add_subdirectory(tests) endif() ``` ## Writing GoogleTest unit tests - Include GoogleTest: `#include <gtest/gtest.h>` - Prefer fast, deterministic, CPU-only tests by default. - Use fixtures (`TEST_F`) when setup/teardown is shared. - Avoid depending on external files unless the test is explicitly a data-driven/integration test. ## Registering tests with `smith_add_tests` `smith_add_tests` creates **one test executable per source file** and registers it with CTest. The executable/test name is the source basename (e.g., `test_state_manager.cpp` → `test_state_manager`). Minimal `tests/CMakeLists.txt` template: ```cmake set(my_component_test_depends smith_my_component gtest) set(my_component_test_sources test_feature_a.cpp test_feature_b.cpp) smith_add_tests(SOURCES ${my_component_test_sources} DEPENDS_ON ${my_component_test_depends} NUM_MPI_TASKS 1) ``` Notes: - Keep test source basenames unique across the project (CMake targets are global). - Add only the libraries you need to `DEPENDS_ON` (the library under test + `gtest` + any required Smith/TPL targets). ### MPI / OpenMP tests If a test requires MPI, add the MPI dependency and set `NUM_MPI_TASKS`: ```cmake smith_add_tests(SOURCES my_parallel_test.cpp DEPENDS_ON gtest blt::mpi smith_my_component NUM_MPI_TASKS 4) ``` If a test requires OpenMP, set `NUM_OMP_THREADS` accordingly. ### CUDA-enabled unit tests If you need a CUDA-enabled unit test, gate it behind `SMITH_ENABLE_CUDA` and pass `USE_CUDA`: ```cmake if(SMITH_ENABLE_CUDA) smith_add_tests(SOURCES my_cuda_test.cpp DEPENDS_ON gtest smith_my_component USE_CUDA TRUE) endif() ``` ## Running tests - Configure with tests enabled: `-DENABLE_TESTS=ON -DSMITH_ENABLE_TESTS=ON` - Run all tests: `ctest` - Run a single test by name: `ctest -R test_state_manager` ## Examples in this repo - Macro definition: `cmake/SmithMacros.cmake` - Typical component tests: `src/smith/physics/state/tests/CMakeLists.txt` - Project-wide tests: `src/tests/CMakeLists.txt`