With the junit-interface runner, there was this handy option:
-q Suppress stdout for successful tests. Stderr is printed to the console normally. Stdout is written to a buffer and discarded when a test succeeds. If it fails, the buffer is dumped to the console. Since stdio redirection in Java is a bad kludge (System.setOut() changes the static final field System.out through native code) this may not work for all scenarios. Scala has its own console with a sane redirection feature. If Scala is detected on the class path, junit-interface tries to reroute scala.Console's stdout, too.
I was wondering whether there was an easy way to make scalatest do the same thing. I can try to redirect the output myself but would prefer to use something standard if possible.