see my comment https://github.com/thomhurst/TUnit/issues/2779#issuecomment-3159927178 it seems it is still not fix in 0.57.1. I've tried with and without constraint keys, my tests are sill The doc says "If no constraint keys are supplied, then the test will only be run by itself". I've only one test in a class that needs to be run "alone", applying `[NotInParallel]` used to work.