In the Gitlab CI environment it would need a tolerance of 140 to succeed. Would that be considered acceptable?
In principle, yes. Testing locally with llvmpipe, I can confirm Zeb's findings though, and adjusting the geometry seems preferable. The attached [patch](/uploads/43f84ecbb02880dc831abcc99f6cb14d/patch.diff) makes it work for me on both llvmpipe and VEGA10.