Socket.IO阻止Mocha退出

Question

我编写了一个小应用程序来学习Socket.IO以及如何对其进行测试。该应用程序仅包含一个服务器文件和一个测试文件。

这是服务器文件：

const app = require('express')();
const http = require('http').createServer(app);
const socketio = require('socket.io')(http);

const io = socketio.listen(http);

io.on('connection', (socket) => {

  delete io.sockets.connected[socket.id];

  const auth_timeout = setTimeout(() => {
    socket.disconnect('unauthorized');
  }, 1000);

  function authenticate(data) {
    clearTimeout(auth_timeout);
    if (!data.uName || data.uName !== 'Bill') {
      socket.emit('disconnectAlert', 'Unauthorized: uName is not Bill');
      socket.disconnect('unauthorized');
    } else {
      io.sockets.connected[socket.id] = socket;

      socket.on('disconnect', () => {
        console.log('Disconnected');
      });

      socket.emit('authenticated');
    }
  }

  socket.on('authenticate', authenticate);
});

function close() {
  io.close();
  http.close();
}

module.exports = {
  server: http,
  close
};

测试文件如下：

const { expect } = require('chai');
const io = require('socket.io-client');

const app = require('./app');

const socketURL = 'http://localhost:3000';

describe('Socket.IO authentication', function() {

  let client;

  before(async function(){
    await app.server.listen(3000);
    console.log('server started');
  });

  after(function(){
    app.close();
  });

  afterEach(function(){
    client.disconnect();
    client.close();
  });

  it('Should connect in two steps', function(done){
    client = io.connect(socketURL);
    let passed = false;

    client.on('connect', () => {
      client.emit('authenticate', { uName: 'Bill' });
    });

    client.on('authenticated', () => {
      expect(true, 'Authenticated').to.be.true;
      passed = true;
      done();
    });

    client.on('disconnect', () => {
      expect(passed, 'Not Authenticated').to.be.true;
      if (!passed) {
        done();
      }
    });
  });

  it('Should be rejected if uName is not Bill', function(done) {
    client = io.connect(socketURL);

    client.on('connect', () => {
      client.emit('authenticate', { uName: 'Mariko' });
    });

    client.on('authenticated', () => {
      expect(false, 'Was authenticated').to.be.true;
      done();
    });

    client.on('disconnectAlert', (msg) => {
      console.log('Inside the test');
      expect(msg).to.be.equal('Unauthorized: uName is not Bill');
      done();
    });
  });
});

两个测试均通过。但是，在第二项测试中使摩卡无法退出。当我仅运行第一个测试时，一切都会顺利进行-测试通过，摩卡退出。但是，当我运行两个测试或仅运行第二个测试时，尽管它通过了，但摩卡卡住了。

有人能看到我在这里做错了什么导致此问题吗？谢谢。