Node.js & Mocha/Should (JavaScript， ES6)：代码未执行，尽管看起来应该执行

Question

我试图使用 mocha/should 和请求在 nodejs 项目中编写一些测试代码。

我的代码使用一些网址初始化一个数组，以便向远程服务器发送 GET 请求并检查响应的内容。

我现在的模型只需要打印出响应，但是由于某种原因，流程永远不会到达那里。

请注意，我有一个 for 循环。在循环中，第一个控制台日志会打印出内容，但是由于某种原因，该循环中的其余代码被跳过。我将断点置于调试模式，但我的代码只到达循环内的第一个 console.log((，并且跳过了请求部分。

我也尝试使用请求的未承诺版本(流和所有(，但我遇到了同样的问题 - 代码从未到达该请求行，所以当然它不会进一步打印任何内容。

它与nodejs中的异步工作有关吗？别的什么？

我错过了什么？

'use strict';
const Promise = require('bluebird')
	, _ = require('underscore')
	, should = require('should')
	, r = require('request')
	, request = Promise.promisifyAll(r.defaults({jar: true}))
	, client = require('../whatever/someClient')
	, testConfig = require('../config/test-config')
;
Promise.longStackTraces();
class someFeatureTestSet {
	
	constructor() {
		//...
		this.client = client.getUser();
		//...
	}
	
	static create() { return new someFeatureTestSet(); }
	
//... some other consts and functions
	
	initURLs(someUrlParamVal) {
		return Array
		.apply(null, Array(someUrlParamVal))
		.map((x, idx) =>
			`http://example.com/whatever?c=${someUrlParamVal}`
		);
	}
	
	runTests() {
		const client = this.client;
		const someFeatureTestSet = this;
		
		describe('get stuff', () => {
			
			it('should bla', () => {
				const productsLinks = this.initURLs('123');
				for (let x in productsLinks) {
					console.log(productsLinks[x]); //gets printed, no problem
					request.getAsync({ uri: productsLinks[x] }) 
					.then(res => { //code never gets here. why?
						console.log(res); //code never gets here. why?
					})
				}
			});
			
		} );
		
	}
	
}
module.exports = someFeatureTestSet;
const createTestSet = () => someFeatureTestSet.create();
createTestSet().client().runTests();

Answer 1

您需要在运行异步测试后返回 Promise 或调用done()回调。由于您在循环中运行异步请求，因此您需要在数组中累积请求承诺并使用Promise.all()

it('should bla', () => {
const productsLinks = this.initURLs('123');
let requests = [];
for (let x in productsLinks) {
console.log(productsLinks[x]); //gets printed, no problem
requests.push(request.getAsync({ uri: productsLinks[x] }));
}
return Promise.all(requests);
});

如果要使用done()可以执行以下操作 -

it('should bla', (done) => {
const productsLinks = this.initURLs('123');
let requests = [];
for (let x in productsLinks) {
console.log(productsLinks[x]); //gets printed, no problem
requests.push(request.getAsync({ uri: productsLinks[x] }));
}
Promise
.all(requests)
.then(() => {
done();
})
});

请注意，如果调用done()超过为运行 mocha 测试设置的超时，它将失败。请参阅此处以了解更多信息 - https://mochajs.org/#timeouts

Answer 2

正如我怀疑的那样，问题在于彻底误解了 Node.js 的事件循环和 Mocha 使用承诺而不是旧的"完成"回调。

以下解决方案对我有用：

'use strict';
const Promise = require('bluebird')
	, _ = require('underscore')
	, should = require('should')
	, r = require('request')
	, request = Promise.promisifyAll(r.defaults({jar: true}))
	, client = require('../whatever/someClient')
	, testConfig = require('../config/test-config')
;
Promise.longStackTraces();
class someFeatureTestSet {
	
	constructor() {
		//...
		this.client = client.getUser();
		//...
	}
	
	static create() { return new someFeatureTestSet(); }
	
//... some other consts and functions
	
	initURLs(someUrlParamVal) {
		return Array
		.apply(null, Array(someUrlParamVal))
		.map((x, idx) =>
			`http://example.com/whatever?c=${someUrlParamVal}`
		);
	}
	
	runTests() {
		const client = this.client;
		const someFeatureTestSet = this;
		
		describe('get stuff', () => {
			
			it('should bla', () => {
				const productsLinks = this.initURLs('123');
				return Promise.map(productsLinks, productsLink => 
					return request.getAsync({uri: productsLink })
						.then(res => { console.log(res) });
				);
			});
			
		} );
		
	}
	
}
module.exports = someFeatureTestSet;
const createTestSet = () => someFeatureTestSet.create();
createTestSet().client().runTests();