i dont understand why everyone just doesn't do this unless they are working with really large volumes of test data. it literally takes a fraction of a second to mkdir, call pginit, and open a postgres socket.

idk if you've solved this, but PG doesn't like to bind to 0, so you have to manage ports. And I've had issues with processes sticking around if the test driver has crashed (I dont currently, but i'm turning off setsid in postgres).