摩卡正确运行,但显示未定义

我使用mocha来testing我的nodejs代码,testing运行正常,但是当我使用mocha test.js来运行testing时,似乎我传递给describe的string不显示。

代码如下:

 var assert = require("should"); describe("FrontEndTest", function(){ describe('websocket establish connection', function(){ it('should establish connection correctly', function(done){ var res; var wsClient = create_ws_client('ws://127.0.0.1:9876','brain_burst'); wsClient.on('connect', function(connection){ res = true; res.should.be.true; done(); }); wsClient.on('connectFailed', function(error){ res = false; res.should.be.true; done(); }); console.log(res); }); it('should disconnected by server.(also, that may crash server if there is not a protocol validation)', function(done){ var res; var wsClient = create_ws_client('ws://127.0.0.1:9876'); wsClient.on('connect', function(connection){ res = true; res.should.be.false; done(); }); wsClient.on('connectFailed', function(error){ res = false; res.should.be.false; done(); }); }); }); }); 

mocha指令的结果显示:

undefined ..

✔完成2个testing(68毫秒)

为什么它显示undefined因为我已经传递一个string?

是不是下面的线导致它?

 console.log(res);