使用 Sinon.JS 模拟 JavaScript 构造函数
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Mocking JavaScript constructor with Sinon.JS
提问by krl
I'd like to unit test the following ES6 class:
我想对以下 ES6 类进行单元测试：
// service.js
const InternalService = require('internal-service');
class Service {
constructor(args) {
this.internalService = new InternalService(args);
}
getData(args) {
let events = this.internalService.getEvents(args);
let data = getDataFromEvents(events);
return data;
}
}
function getDataFromEvents(events) {...}
module.exports = Service;
How do I mock constructor with Sinon.JS in order to mock getEventsof internalServiceto test getData?
我如何模拟构造与Sinon.JS以嘲笑getEvents的internalService测试getData？
I looked at Javascript: Mocking Constructor using Sinonbut wasn't able to extract a solution.
我查看了Javascript: Mocking Constructor using Sinon，但无法提取解决方案。
// test.js
const chai = require('chai');
const sinon = require('sinon');
const should = chai.should();
let Service = require('service');
describe('Service', function() {
it('getData', function() {
// throws: TypeError: Attempted to wrap undefined property Service as function
sinon.stub(Service, 'Service').returns(0);
});
});
采纳答案by victorkohl
You can either create a namespace or create a stub instance using sinon.createStubInstance(this will not invoke the constructor).
您可以使用创建命名空间或创建存根实例sinon.createStubInstance（这不会调用构造函数）。
Creating a namespace:
创建命名空间：
const namespace = {
Service: require('./service')
};
describe('Service', function() {
it('getData', function() {
sinon.stub(namespace, 'Service').returns(0);
console.log(new namespace.Service()); // Service {}
});
});
Creating a stub instance:
创建存根实例：
let Service = require('./service');
describe('Service', function() {
it('getData', function() {
let stub = sinon.createStubInstance(Service);
console.log(stub); // Service {}
});
});
