Converting an OutputStream to an InputStream

This old problem again... I need an input stream in my test - but how do I create it? This guy knows. Thanks!

     final PipedOutputStream pout = new PipedOutputStream();
     new Thread(new Runnable(){
        public void run(){
         DataOutput output = new DataOutputStream(pout);
                        // write to output stream here
        }
      }
    ).start();
     DataInputStream in = new DataInputStream(new PipedInputStream(pout));