- [x] Have you followed the [guidelines for contributing](https://github.com/snapcore/snapcraft/blob/master/CONTRIBUTING.md)? - [x] Have you signed the [CLA](http://www.ubuntu.com/legal/contributors/)? - [x] Have you successfully run `make lint`? - [x] Have you successfully run `pytest tests/unit`? ----- Core22 ROS 2 `colcon` snaps couldn't build packages creating custom ROS 2 interfaces. It was sourcing the environment before downloading the dependencies. Some dependencies (`rosidl`) have specificities when sourced, hence sourcing before downloading them causes issues. In the case of ROS 2 message, the `PYTHONPATH` only had the `site-packages` subdir and not the `dist-packages` subdir added by `rosidl`. This issue couldn't appear with `lxd` spread tests because the `lxd` environment was not cleaned properly by `colcon` spread tests (Debian packages were still installed, hence the dependencies were mostly already installed). Additionally, the advanced `colcon` spread tests had no entry in the `spread.yaml` and were never called. Hence, this PR does: - Add missing spread entry for `colcon` specific tests - Add `package-utils.sh` to restore the state of Debian package installed before a spread tests - Add a `colcon` spread test with a message package to highlight that there is a bug - Fix the bug by sourcing the ROS 2 environment after installing the ROS 2 dependencies