test: add unit tests for create_callback_group_id

[ran2810]

Description

Adds unit tests for create_callback_group_id (cie_thread_configurator/src/util.cpp), addressing the first unit-test item in #38.

Covers:

• Root namespace produces a single leading slash (/node, not //node)
• Non-root namespace path (/ns/node)
• The trailing @ separator is stripped from the result
• Timer entities are identified by period in nanoseconds
• The Node overload matches the NodeBaseInterface overload

Tests use ament_add_ros_isolated_gtest so each case runs in an isolated ROS context.

Related links

Part of #38

How was this PR tested?

Built and ran locally on ROS 2 Humble:

• colcon test --packages-select cie_thread_configurator — all 5 gtest cases pass
• pre-commit run --files ... passes (clang-format clean)

Note: the gtest target is not picked up by the current CI test step, which filters to -L launch_test. Wiring CI to run gtest unit tests is itself an open item in #38 and is out of scope for this PR.

Notes for reviewers

• Scope is limited to create_callback_group_id unit tests only, per the suggested starting point in test: add unit and integration tests #38.
• The pre-existing ament linter failures (copyright/cpplint/uncrustify) on other files in the package are unrelated to this change and not addressed here.

[Copilot]

Pull request overview

Adds isolated ROS 2 unit tests for cie_thread_configurator::create_callback_group_id, improving regression coverage for callback-group ID formatting behavior described in #38.

Changes:

• Add ament_add_ros_isolated_gtest-based gtests covering namespace formatting, trailing separator stripping, timer period encoding, and overload consistency.
• Extend cie_thread_configurator test dependencies to include ament_cmake_ros and std_msgs.
• Register the new test_util target in cie_thread_configurator/CMakeLists.txt.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

File	Description
cie_thread_configurator/test/test_util.cpp	Adds isolated gtests validating create_callback_group_id string formatting across several entity/namespace cases.
cie_thread_configurator/package.xml	Adds test dependencies needed by the new isolated gtest and message type used in the test.
cie_thread_configurator/CMakeLists.txt	Adds isolated gtest target and test-only package discovery (but currently needs target-order fix).

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[atsushi421]

The tests cover only Subscription and Timer, but create_callback_group_id also handles Service, Client, and Waitable entities and joins multiple entities with '@'. The multi-entity case (the internal '@' join and the collect_all_ptrs ordering) is never exercised, and the trailing-'@' test only proves single-entity suffix removal. Consider adding tests for a Service, a Client, and a group with 2+ entities that asserts the joined ordering.

[atsushi421]

Thank you for your contribution! Could you address the comments above and use the AAA pattern for unit tests?

[ran2810]

Thanks for the thorough review @atsushi421! Addressed all comments:

Added Service, Client, and a multi-entity test asserting the full @-joined string. The multi-entity test pins the actual collect_all_ptrs emission order, which turned out to be subscription → service → client → timer.
Replaced the trailing-@ test with an empty-group case asserting the result equals exactly /test_node, so it exercises the stripping path directly.
Removed the redundant cie_config_msgs from ament_target_dependencies.
Restructured all tests using the AAA pattern.

All 8 tests pass locally and pre-commit is clean. Ready for another look.

[atsushi421]

@ran2810
LGTM! Merged!