Currently many packages (mostly message generators) have their own test interface to check if the generator works as expected. But each package has an arbitrary subset. And with the amount of corner cases and variations it would be helpful if all these interface files exist in a single location. The message generator packages can't depend on test_msgs since that package itself depends on all message generators.

To avoid the duplication and get rid of the differences of these interface files I would like to propose to extract the actual interface files from the test_msgs package into a new separate package (and repository). I would propose the package / repo name test_interface_files. The test_msgs package would then be updated to still invoke the message generation for all these files - just not contain the interface files anymore but get them from the new package.

I am mostly looking for feedback on this before actually spending the time to create PRs for it.