使用Karma做vue组件单元测试的实现

// Karma configuration

const webpackConfig = require('./config/webpack.test.config.js')

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' ],

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

  // preprocess matching files before serving them to the browser
  // available preprocessors: https://npmjs.org/browse/keyword/karma-preprocessor
  preprocessors: {
   'test/**/*.spec.js': [ 'webpack', 'sourcemap' ]
  },

  // webpack config
  webpack: webpackConfig,

  webpackMiddleware: {
   stats: 'errors-only'
  },

  // 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: [ 'Chrome' ],

  // 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
 })
}

import { expect } from 'chai'
import { shallowMount } from '@vue/test-utils'
import Header from '../src/components/Header'

describe('Header', () => {
 const wrapper = shallowMount(Header)
 const header = wrapper.find('header')
 const h1 = wrapper.find('h1')

 it('有 header 标签', () => {
  expect(header.exists()).to.be.true
 })

 it('有 h1 标签', () => {
  expect(h1.exists()).to.be.true
 })

 it('h1 的文案为“VUE 单页模版”', () => {
  expect(h1.text()).to.equal('VUE 单页模版')
 })

 it('h1 标签在 header 标签中', () => {
  expect(header.contains('h1')).to.be.true
 })
})

const merge = require('webpack-merge')
const path = require('path')
const webpackCommonConfig = require('./webpack.common.config')

const testConfig = {
 devtool: 'inline-source-map',
 mode: 'none',
 module: {
  rules: [
   {
    test: /.spec.js$/i,
    enforce: 'pre',
    use: [
     {
      loader: 'istanbul-instrumenter-loader',
      options: {
       esModules: true
      }
     }
    ]
   }
  ]
 }
}

module.exports = merge(webpackCommonConfig, testConfig)

module.exports = function(config) {
 config.set({
 
  // ...
  
  coverageIstanbulReporter: {
   reports: [ 'html', 'text' ],
   fixWebpackSourcePaths: true
  },
  
  reporters: [ 'coverage-istanbul' ]

  //...
  
 })
}

----------------|----------|----------|----------|----------|-------------------|
File      | % Stmts | % Branch | % Funcs | % Lines | Uncovered Line #s |
----------------|----------|----------|----------|----------|-------------------|
All files    |   100 |   100 |   100 |   100 |          |
 Header.spec.js |   100 |   100 |   100 |   100 |          |
----------------|----------|----------|----------|----------|-------------------|