Okay I see. Then I'd remove this sample from here and put it into a repl test in `test/files/run`. 

Here's an example repl test: https://github.com/xeno-by/scala/blob/4c62f7db6f3913eedd92d85daf8f631149cc97b2/test/files/run/macro-repl-basic.scala#L1. You'll probably have to override some initialization that's done in `ReplTest` to plug in your custom formatter.