我是 Junit 测试用例世界的新手,我只是想知道我是否开发了一个程序
class MapDemo1
{static final Logger logger = Logger.getLogger(MapDemo1.class);
     /**
     *  
     */
    public static void main(String arg[])
     {PropertyConfigurator.configure("src/log4j.properties");
     logger.info("-->Map");
    // Map map=new TreeMap();
         Map map=new HashMap();//HashMap key random order.
      //   System.out.println("Amit".hashCode());
         map.put("Amit","Java");
         map.put("Amit","Javas");
        // map.put("mAit","J2EE");
         //map.put("Saral","J2rrrEE");
         /*map.put("ty","Spring");
         map.put("Anupam","Hibernate");
         map.put("Ravi",".Net");
         map.put("Saral","Andriod");//same key but different value 
         map.put("Nitin","PHP");
         map.put("hj","Spring1");*/
         System.out.println("There are "+map.size()+" elements in the map.");
         System.out.println("Content of Map are...");
         Set s=map.entrySet();
         Iterator itr=s.iterator();
         while(itr.hasNext())
         {
             Map.Entry m=(Map.Entry)itr.next();
             System.out.println(m.getKey()+"\t"+m.getValue()+"\t"+ m.hashCode());
          }
]
}
现在请告知什么是 junit 测试用例,以及它们将如何在单独的类中编写。