On my current pet project, it has written almost all of the tests here: https://github.com/golergka/rs-lox/blob/master/src/compiler.... ad here: https://github.com/golergka/rs-lox/blob/master/src/scanner.r... (albeit not the screwed indentation) completely by itself. I didn't even have to write the function names, just a few macros to help it along and a couple of examples to teach it to use it.