remove conceptual dependency on ROS_DOMAIN_ID in launch_testing

[wjwwood]

Currently launch_testing has options/features related to ROS_DOMAIN_ID:

launch/launch_testing/launch_testing/launch_test.py

Line 51 in 066009b

# TODO(hidmic): Provide this option for rostests only.

This should not be the case, it is inappropriate for anything in this repository to depend on, reference, or really even mention anything from ROS.

There's a TODO, which I linked to, but I opened this issue to raise the severity. This needs to be changed.

@hidmic @pbaughman please don't let things like this leak into launch or launch_testing in the future.

[pbaughman]

Do you have any suggestions about how to fix it? The cure (removing this) seems worse than the disease right now

[pbaughman]

Could we add an extension point to launch_test so that when launch_testing_ros is installed you get the isolation behavior?

[pbaughman]

I guess we could also add a different runner with a different name to run tests that need ROS

[hidmic]

This should not be the case, it is inappropriate for anything in this repository to depend on, reference, or really even mention anything from ROS.

I fully agree. As it stands, this option could be moved to the ros2test CLI command with little to no effort (owing to the fact it's just an envvar).

[pbaughman]

@hidmic will we add a different cmake function that calls the ros2cli command? The dependency graph for that cmake function will be quite long, but maybe not that much longer than launch_ros

[hidmic]

@pbaughman there is one already, add_ros_test().

[pbaughman]

@hidmic I want to refactor the domain coordinator into its own package so I can do this ament/ament_cmake#172 so lets's make sure we coordinate on this.

[ivanpauno]

@hidmic I want to refactor the domain coordinator into its own package so I can do this ament/ament_cmake#172 so lets's make sure we coordinate on this.

Sounds good. Where should the domain coordinator live?
If it doesn't fit well in an existing repo, I will need a new one (I can't create a new one).

[pbaughman]

@ivanpauno In the WIP I've got now, it lives in ament_cmake_ros along with a new ament_cmake_pytest_isolated and an ament_cmake_gtest_isolated package

[ivanpauno]

@ivanpauno In the WIP I've got now, it lives in ament_cmake_ros along with a new ament_cmake_pytest_isolated and an ament_cmake_gtest_isolated package

I think ament_cmake_pytest_isolated and ament_cmake_gtest_isolated should live in ament_cmake_ros. But the code of the domain coordinator could be in a separated repo, as it is really a python package (and not cmake stuff). It's ok for me having it there though.

[pbaughman]

@ivanpauno Let's talk about it in the MR once I open it, but there's one cmake thing that I jammed into the domain_coordinator package - it might make sense to move it, or it might not.