feat(pointcloud_preprocessor): add test for distortion correction node

[vividf]

Description

Add Integration testing for the distortion correction node.

• test empty twist
• test empty imu
• test empty pointcloud
• test normal input without using imu msg
• test normal input using imu msg

Related links

Tests performed

Build

colcon build --symlink-install --cmake-args -DCMAKE_BUILD_TYPE=Release --packages-select pointcloud_preprocessor

Test

colcon test --packages-select pointcloud_preprocessor --event-handlers console_cohesion+

Notes for reviewers

Interface changes

ROS Topic Changes

ROS Parameter Changes

Effects on system behavior

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[knzo25]

I saw you are addressing directly the data of the pointcloud. In python there are still ways to access pointclouds via iterators. If not that approach, ros2_numpy would be an option, but probably not possible in universe. However, I highly recommend you re write pointcloud related tests to c++

On another note, please avoid using don't and similar abbreviations. They have leaked into other parts where they should not been before

[vividf]

@knzo25

Thanks for the review,
I agree that writing C++ tests is better for testing, however, this PR is not a Unit test but an Integration test (which tests the single node instead of the function). Regarding the Integration testing on the Autoware contribution (testing the output of node), it suggests us to write in this way. Therefore, I am not sure that I should spend more time migrating it to the C++ version in this case.

I saw you are addressing directly the data of the pointcloud. In python there are still ways to access pointclouds via iterators. If not that approach, ros2_numpy would be an option, but probably not possible in universe.

For this comment, could you explain more in detail, Thanks!

[knzo25]

An integration test is defined as the phase in software testing where individual software modules are combined and tested as a group. Integration tests occur after unit tests, and before validation tests.

The input to an integration test is a set of independent modules that have been unit tested. The set of modules is tested against the defined integration test plan, and the output is a set of properly integrated software modules that is ready for system testing.

Having the briefest of looks your test is a unit test, since anyways the distortion correction has essentially one method

[vividf]

This PR is set to draft as we want the gtest instead of the component test.

[vividf]

The unit test is created by another PR #7801
Therefore, this pr will be closed.