我是JUnit测试的新手，我已经编写了将文件重定向为输入的代码，但是我不确定如何测试它。测试代码的最佳方法是什么？

private static String request;

public static void main(String[] args) {
   readFile();
}

public static void readFile() {

    try {
       /* BufferedReader to read text from an input stream */
       BufferedReader input = new BufferedReader(new InputStreamReader(System.in));

       /* While loop to read each line of the file. request - each line is a different client request */ 
       while ((request = input.readLine()) != null) {
        System.out.println("Client request: " + request);
       }

       /* Closes input */
       input.close();
    }
    catch (Exception e) {
        e.printStackTrace();
    }
}