In theory yes, in practice really weird trouble getting sbt to do that, I think I'll open a low-prio task for it.

One way is `TestsListener`s, but that does not seem to be called (doInit / doComplete) for the case of root level aggregate project. Otherwise, it would be called for every sub project - so I'd have to track in a var "have i notified about this build already?" etc. Really dodgy. Other option is the use of the current flow, but `Def.taskDyn` is quite weird (macro maddness) to get right...