code:     public void setUp() throws Exception {
          interceptor = new I18nInterceptor();
          interceptor.init();
          params = new HashMap<String, Object>();
          session = new HashMap();
  
          Map<String, Object> ctx = new HashMap<String, Object>();
          ctx.put(ActionContext.PARAMETERS, params);
          ctx.put(ActionContext.SESSION, session);
          ac = new ActionContext(ctx);
  
          Action action = new Action() {
              public String execute() throws Exception {
                  return SUCCESS;
              }
          };
          mai = new MockActionInvocation();
          ((MockActionInvocation) mai).setAction(action);
          ((MockActionInvocation) mai).setInvocationContext(ac);
      }
  
      @After
  