Moveit: failing unittest on ROS build server

[rhaschke]

The unittest MoveItConfigData.ReadingControllers fails for some reason on the ROS build server,
while there is no issue on Travis:
http://build.ros.org/job/Mdev__moveit__ubuntu_bionic_amd64/47/testReport/(root)/MoveItConfigData/ReadingControllers/
http://build.ros.org/job/Kdev__moveit__ubuntu_xenial_amd64/lastCompletedBuild/testReport/(root)/MoveItConfigData/ReadingControllers/

@MohmadAyman: Could you have a look, please?

[MohmadAyman]

I believe that have sth to do with the tests trying to write a ros_controllers.yaml to moveit_resources which is in /opt.
Unable to open file for writing /opt/ros/melodic/share/moveit_resources/ros_controller.yaml

I'm guessing Travis has moveit_resources built from source thats why it doesn't fail, or it runs the tests as a su.

I'm not sure what is the difficulty of modifying the ros build server, well since we only need a temp path for this file, we can try to come up with a path that would work.

[v4hn]

Unable to open file for writing /opt/ros/melodic/share/moveit_resources/ros_controller.yaml

Nothing should ever try to write to a package path.
If you need a temporary file, it's usually a good idea to use mkstemp et al,
but I did not look at the concrete case

[davetcoleman]

Indeed, the test should write to a temp location. @MohmadAyman can you propose a PR for this?

However this may not be supported at all by GTest in which case, maybe we can output the file to memory then read it again from memory without an actual file hit?

[MohmadAyman]

This commit should fix this issue.

I know it is not very related to the PR, but it is a small commit, still I dont mind separating it into another PR.

[rhaschke]

This commit should fix this issue.
@MohmadAyman It would have been better to file a separate PR for this.

[MohmadAyman]

Open pull request #1042 to solve this issue.

[davetcoleman]

Closed for now by https://github.com/ros-planning/moveit/pull/1042, reopen if build farm still is failing