Try installing dependencies of vtk package in test jobs
* Install python3-vtk7 non-interactively. * Install libxt-dev to see if this suffices.
The TS-GitLab will have to shut down towards the end of the year — please think about migrating your projects to GitLab.com or GitHub.
(This is still a very early message, meant to keep you informed. There will be more urgent ones in the future.)