使用 Karma + Mocha做自动化测试，以及解决报错

步骤

1. 安装各种工具

npm i -D karma karma-chrome-launcher karma-mocha karma-sinon-chai mocha sinon sinon-chai karma-chai karma-chai-spies

2. 创建 karma 配置

新建文件 karma.conf.js，内容如下

module.exports = function (config) {
     config.set({

         // base path that will be used to resolve all patterns (eg. files, exclude)
         basePath: '',
            // frameworks to use
            // available frameworks: https://npmjs.org/browse/keyword/karma-adapter
            frameworks: ['mocha', 'sinon-chai'],
            client: {
                chai: {
                    includeStack: true
                }
            },


            // list of files / patterns to load in the browser
            files: [
                'dist/**/*.test.js',
                'dist/**/*.test.css'
            ],


            // list of files / patterns to exclude
            exclude: [],


            // preprocess matching files before serving them to the browser
            // available preprocessors: https://npmjs.org/browse/keyword/karma-preprocessor
            preprocessors: {},


            // test results reporter to use
            // possible values: 'dots', 'progress'
            // available reporters: https://npmjs.org/browse/keyword/karma-reporter
            reporters: ['progress'],


            // web server port
            port: 9876,


            // enable / disable colors in the output (reporters and logs)
            colors: true,


            // level of logging
            // possible values: config.LOG_DISABLE || config.LOG_ERROR || config.LOG_WARN || config.LOG_INFO || config.LOG_DEBUG
            logLevel: config.LOG_INFO,


            // enable / disable watching file and executing tests whenever any file changes
            autoWatch: true,


            // start these browsers
            // available browser launchers: https://npmjs.org/browse/keyword/karma-launcher
            browsers: ['ChromeHeadless'],


            // Continuous Integration mode
            // if true, Karma captures browsers, runs the tests and exits
            singleRun: false,

            // Concurrency level
            // how many browser should be started simultaneous
            concurrency: Infinity
        })
    }

3. 创建 test/button.test.js 文件

const expect = chai.expect;
 import Vue from 'vue'
 import Button from '../src/button'

 Vue.config.productionTip = false
 Vue.config.devtools = false

 describe('Button', () => {
     it('存在.', () => {
         expect(Button).to.be.ok
     })
     it('可以设置icon.', () => {
         const Constructor = Vue.extend(Button)
         const vm = new Constructor({
         propsData: {
             icon: 'settings'
         }
         }).$mount()
         const useElement = vm.$el.querySelector('use')
         expect(useElement.getAttribute('xlink:href')).to.equal('#i-settings')
         vm.$destroy()
     })
     it('可以设置loading.', () => {
         const Constructor = Vue.extend(Button)
         const vm = new Constructor({
         propsData: {
             icon: 'settings',
             loading: true
         }
         }).$mount()
         const useElements = vm.$el.querySelectorAll('use')
         expect(useElements.length).to.equal(1)
         expect(useElements[0].getAttribute('xlink:href')).to.equal('#i-loading')
         vm.$destroy()
     })
     it('icon 默认的 order 是 1', () => {
         const div = document.createElement('div')
         document.body.appendChild(div)
         const Constructor = Vue.extend(Button)
         const vm = new Constructor({
         propsData: {
             icon: 'settings',
         }
         }).$mount(div)
         const icon = vm.$el.querySelector('svg')
         expect(getComputedStyle(icon).order).to.eq('1')
         vm.$el.remove()
         vm.$destroy()
     })
     it('设置 iconPosition 可以改变 order', () => {
         const div = document.createElement('div')
         document.body.appendChild(div)
         const Constructor = Vue.extend(Button)
         const vm = new Constructor({
         propsData: {
             icon: 'settings',
             iconPosition: 'right'
         }
         }).$mount(div)
         const icon = vm.$el.querySelector('svg')
         expect(getComputedStyle(icon).order).to.eq('2')
         vm.$el.remove()
         vm.$destroy()
     })
     it('点击 button 触发 click 事件', () => {
         const Constructor = Vue.extend(Button)
         const vm = new Constructor({
         propsData: {
             icon: 'settings',
         }
         }).$mount()

         const callback = sinon.fake();
         vm.$on('click', callback)
         vm.$el.click()
         expect(callback).to.have.been.called

     })
 })

4. 创建测试脚本

在 package.json 里面找到 scripts 并改写 scripts

"scripts": {
     "dev-test": "parcel watch test/* --no-cache & karma start",
     "test": "parcel build test/* --no-cache --no-minify && karma start --single-run"
 },

5. 运行测试脚本

1. 要么使用 npm run test 一次性运行
2. 要么使用 npm run dev-test 进行 watch 运行

遇到报错

22 04 2022 09:22:10.219:ERROR [karma-server]: Server start failed on port 9876: Error [ERR_PACKAGE_PATH_NOT_EXPORTED]: Package subpath './package.json' is not defined by "exports" in /Users/bumble/myProjects/gulu-ui/node_modules/sinon/package.json
npm ERR! code ELIFECYCLE
npm ERR! errno 1
npm ERR! gulu@0.0.1 test: `parcel build test/* --no-cache --no-minify && karma start --single-run`
npm ERR! Exit status 1
npm ERR! 
npm ERR! Failed at the gulu@0.0.1 test script.
npm ERR! This is probably not a problem with npm. There is likely additional logging output above.

npm ERR! A complete log of this run can be found in:
npm ERR!     /Users/bumble/.npm/_logs/2022-04-22T01_22_10_249Z-debug.log

最后发现是node版本低，解决办法：下载node版本v16.13.0

mac下载 node v16.13.0 操作：

1. 清除下nodejs的缓存sudo npm cache clean -f
2. 使用npm全局安装n模块sudo npm install -g n
3. 下载具体的版本号sudo n 16.13.0

其他报错

可尝试清除缓存rm -rf .cache dist后再跑项目。