基于Nodeunit测试事件的异步代码 [英] Nodeunit testing event based async code

问题描述

过去几天我已经发布了几个问题，太长了（我猜，因为我没有收到任何非隐私的反馈）。以下代码使用setup-complete事件来通知nodeunit setUp命令来运行测试。测试1通过，测试2失败与

失败：未测试（或其设置/拆除）：
- 基于事件的异步代码 - test2

我的代码有一些错误吗？ nodeunit是测试基于事件代码的不好选择吗？我的做法
任何建议赞赏。感谢

async_setup.js：

  var 
事件= require（'events'），
 setup = new events.EventEmitter; 
 
 module.exports = function（app，cb）{
 setup.on（'setup-complete'，function（）{
 cb（）; 
} ）; 
 setTimeout（function（）{
 if（app.result）throw new Error（AlreadyConfiguredAppError）; 
 app.result =app is configured; 
 setup.emit （'setup-complete'，app.result）; 
}，5000）; 
 return app; 
}; 
  

test / test.js：

  var 
 nodeunit = require（'nodeunit'），
 async_setup = require（'../async_setup'）; 
 
导出['基于事件的异步代码'] = nodeunit.testCase（{
 setUp：function（callback）{
 this.app = {}; 
 async_setup （this.app，callback）; 
}，
 
 tearDown：function（callback）{
 delete this.app; 
 callback（）; 
 }，
 
'test1'：function（t）{
 t.expect（1）; 
 t.ok（this.app.result！== undefined，'app配置'）; 
 t.done（）; 
}，
 
'test2'：function（t）{
 t.expect（1）; 
 t.ok（this.app.result！== undefined，'app is configured'）; 
 t.done（）; 
} 
}）; 
  

解决方案

问题最终是事件侦听器设置测试之间不会被破坏。我通过修改setUp函数来修复问题，以使用proxyquire与noPreserveCache标志设置：

  var proxyquire = require（'proxyquire' ）; 
 ... 
 
 setUp：function（callback）{
 this.app = {}; 
 proxyquire.noPreserveCache（）; 
 var async_setup = proxyquire（'../async_setup'，{}）; 
 async_setup（this.app，callback）; 
} 
  

Webstorm中的错误消息有更多的信息，堆栈跟踪到nodeunit异步模块错误：

  iterator（x.value，function（err，v）{
无法读取属性值'未定义的
  

当我浏览代码时，我注意到有两个事件侦听器设置，即使我

希望这有助于别人在那里。

I've already posted a few question the past few days, which were too long (I'm guessing because I didn't receive any non cryptic feedback). I've tried to make this brief.

The following code uses a 'setup-complete' event to notify the nodeunit setUp command to run the tests. Test 1 passes, test 2 fails with

FAILURES: Undone tests (or their setups/teardowns): - event based async code - test2

Is there some mistake in my code? Is nodeunit a bad choice for testing event based code? Is my approach? Any advice appreciated. thanks

async_setup.js:

var
  events = require( 'events' ),
  setup  = new events.EventEmitter;

module.exports = function ( app, cb ) {
  setup.on( 'setup-complete', function () {
    cb();
  });
  setTimeout( function () {
    if ( app.result ) throw new Error( "AlreadyConfiguredAppError" );
    app.result = "app is configured";
    setup.emit( 'setup-complete', app.result );
  }, 5000 );
  return app;
};

test/test.js:

var
  nodeunit = require( 'nodeunit' ),
  async_setup = require( '../async_setup' );

exports[ 'event based async code' ] = nodeunit.testCase({
  setUp: function ( callback ) {
    this.app = {};
    async_setup( this.app, callback );
  },

  tearDown: function ( callback ) {
    delete this.app;
    callback();
  },

  'test1': function ( t ) {
    t.expect( 1 );
    t.ok( this.app.result !== undefined, 'app is configured' );
    t.done();
  },

  'test2': function ( t ) {
    t.expect( 1 );
    t.ok( this.app.result !== undefined, 'app is configured' );
    t.done();
  }
});

解决方案

The problem ended up being that the event listeners setup weren't being destroyed between tests. I fixed the issue by modifying the setUp function to use proxyquire with the noPreserveCache flag set:

var proxyquire = require( 'proxyquire' );
...

setUp: function ( callback ) {
  this.app = {};
  proxyquire.noPreserveCache();
  var async_setup = proxyquire( '../async_setup', {} );
  async_setup( this.app, callback );
}

The error message in Webstorm had more info, with a stack trace to a nodeunit async module error:

iterator(x.value, function (err, v) {
Cannot read property 'value' of undefined

When I stepped through the code I noticed that there were two event listeners setup even though I only set one in the test.

Hope this helps someone else out there.

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