What I was thinking was some improvements to gnattest (https://docs.adacore.com/gnat_ugn-docs/html/gnat_ugn/gnat_ug...) but also a way to add some quickcheck-like generator features (Ada already has the property description language through contracts) with Libadalang... One can dream !
But the whole "Let the developer write one test harness and use it almost as-is with different testing/validation techs" (I'm not explaining it well) was some kind of revelation.
When you say 'adding a fuzzing test harness is only 2-3 days work' you still get complaints: that's too much (but I then found dozens of bugs), it's /another/ test harness to maintain, we'll have to rebuild an input corpus for every interface break (true...). Anything that could alleviate the pain would be great...