public void runTests()
        throws IOException
    {
        String inputLine;
        while ((inputLine = input.readLine()) != null) {
            if (inputLine.trim().length() == 0 ||
                inputLine.charAt(0) == '#') {
                // echo blank and comment lines
                output.println(inputLine);
                continue;
            }

            // separate the input line on white space
            StringTokenizer st = new StringTokenizer(inputLine);
            if (st.hasMoreTokens()) {
                String command = st.nextToken();

                List<String> arguments = new ArrayList<String>();
                while (st.hasMoreTokens()) {
                    arguments.add(st.nextToken());
                }

                executeCommand(command, arguments);
            }

        }
        output.flush();
    }