test: add unit and integration tests

[atsushi421]

Summary

The project currently has no unit tests (only one integration/launch test exists). Tests should be added to ensure correctness and prevent regressions.

Scope

Unit tests (pure logic, via ament_add_ros_isolated_gtest)

• cie_thread_configurator::create_callback_group_id: self-contained string-ID generation; good starting point
• MultiThreadedExecutorInternal state machine / error handling: pre_spin() called twice throws, spin() without pre_spin() throws, get_thread_ids() without pre_spin() throws, and get_thread_ids() returns N unique TIDs
• CallbackIsolatedExecutor add/remove/get bookkeeping for callback groups and nodes
  • Duplicate detection currently calls exit(EXIT_FAILURE), so these paths need gtest death tests (EXPECT_EXIT) unless they are converted to exceptions first (see Testability refactors below)
  • The constructor calls create_client_publisher(), so rclcpp::init() is required; this is not a pure unit test
• ThreadConfiguratorNode YAML/config parsing and error paths (empty config_file, unknown scheduling policy, malformed YAML, hardware mismatch)
  • Requires extracting the parsing logic out of the constructor to make it testable
• PrerunNode dump_yaml_config output and duplicate-ID detection

Integration tests (via launch_testing)

• Minimal pub/sub exercising CallbackIsolatedExecutor directly (test_cie_pubsub.launch.py): test(cie): add minimal pub/sub launch_testing for CIE #57
• Component container path end-to-end (ComponentManagerCallbackIsolated / composable nodes)
  • add_node_to_executor / remove_node_from_executor are protected overrides driven only through ComponentManager's load/unload services, so this is inherently integration rather than unit. The previously separate "unit test for ComponentManagerCallbackIsolated" item is folded in here; only is_clock_callback_group is unit-sized.
• Non-ROS thread path end-to-end (spawn_non_ros2_thread -> NonRosThreadInfo -> non_ros_thread_callback in ThreadConfiguratorNode / PrerunNode)

CI

• Extend the build-and-test workflow to also run gtest unit tests (it currently runs colcon test ... -L launch_test, so ament_add_gtest targets are never executed)
• Widen --packages-select to also cover cie_thread_configurator (only callback_isolated_executor is tested today, so unit tests added to the configurator package would not run otherwise)

[ran2810]

@atsushi421: I'd like to help with this. I see a test/ folder already exists — could you clarify which of the scoped items are already covered and which are still open?

[atsushi421]

Thanks for offering to help, @ran2810! 🙏

Current status:

• ✅ Done: the only test so far is the minimal pub/sub launch test (test_cie_pubsub.launch.py), which exercises CallbackIsolatedExecutor directly.
• ⬜ Open: everything else in the checklist, i.e. the four unit-test items, the component-container end-to-end integration test, and extending CI to run gtest unit tests (CI currently filters to -L launch_test).

If you're looking for a good starting point, unit tests for cie_thread_configurator (e.g. create_callback_group_id) are the most self-contained. Feel free to pick any item and open a PR, happy to review.

[ran2810]

Thanks @atsushi421 ! I'll start with unit tests for cie_thread_configurator, focusing on create_callback_group_id in util.cpp as suggested. Following the ament_add_ros_isolated_gtest pattern. Will open a PR shortly.

[ran2810]

Opened #58 with unit tests for create_callback_group_id (the first unit-test item). It covers the namespace handling, trailing-separator strip, timer period formatting, and overload equivalence, using ament_add_ros_isolated_gtest.

[ran2810]

#58 (merged) covers the cie_thread_configurator unit-test item — the create_callback_group_id tests. The other items (executor unit tests, integration tests, CI integration) are still open.