reg. background mode, see:
- scene.update() usages in https://developer.blender.org/diffusion/B/browse/master/release/scripts/modules/bl_previews_utils/bl_previews_render.py
I'm doing addons now (separate), then addons_contrib (separate), then tests...
So will commit these [unless you want the background cases included as well? I've only tested the background job template, this doesnt give errors when changing to view_layer.update(), but doesnt render correctly -- but wasnt before either, so might be another issue...]