NullPrintStream

class NullPrintStream {
  NullPrintStream()
  void suppressingStdout(Runnable r)
  T suppressingStdout(Callable<T> c)
  void suppressingStderr(Runnable r)
  T suppressingStderr(Callable<T> c)
  void suppressing(Runnable r)
  T suppressing(Callable<T> c)
}