private void sendMessage(DatagramChannel peer1, DatagramChannel peer2, String msg) throws IOException, InterruptedException
    {
        ByteBuffer b = writePacket(peer2, msg);
        
        Thread.sleep(1000);
        b.clear();
        peer1.read(b);
        b.flip();
        
        String actual = HELPER.readString(b, b.remaining());
        assertEquals(msg, actual);
    }