karma和webpack可以是独立出来的，不一定和vue一起用。而karma和webpack也可以是互相独立的。只是说karma.conf可能需要webpack的一些解析es6语法，.css,.js文件的的一些能力(因为webpack里可以加很多loader)。

karma.conf.js

该文件主要就是测试目录的一些基本配置。

// Karma configuration
// Generated on Wed Nov 15 2017 13:37:30 GMT+0800 (CST)
// let webpack = require('webpack')
const webpackEnv = {test: true}
const webpackConfig = require('./build/webpack.base.conf.js')
//此处引入webpack的配置，下面会用到

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: ['jasmine'],


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


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


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

    webpack: webpackConfig,
    webpackMiddleware: {noInfo: true}, // no webpack output


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


    // 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: false,


    // 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
  })
}

webpack.base.conf.js

webpack.base.conf.js在我的项目里涉及到的主要是，需要是在karma不认识.css以及.vue文件时在module项里加上css-loader或者vue-loader.按我的理解就是一个解析器。

'use strict'
const path = require('path')
const utils = require('./utils')
const config = require('../config')
const vueLoaderConfig = require('./vue-loader.conf')

function resolve (dir) {
  return path.join(__dirname, '..', dir)
}

module.exports = {
  entry: {
    app: './src/main.js'
  },
  output: {
    path: config.build.assetsRoot,
    filename: '[name].js',
    publicPath: process.env.NODE_ENV === 'production'
      ? config.build.assetsPublicPath
      : config.dev.assetsPublicPath
  },
  resolve: {
    extensions: ['.js', '.vue', '.json'],
    alias: {
      'vue$': 'vue/dist/vue.esm.js',
      '@': resolve('src'),
    }
  },
  module: {
    rules: [
      {
        test: /\.vue$/,
        loader: 'vue-loader',
        options: vueLoaderConfig
      },
      {
        test: /\.js$/,
        loader: 'babel-loader',
        include: [resolve('src'), resolve('test')],
        exclude: [resolve('server')]
      },
      {
        test: /\.(png|jpe?g|gif|svg)(\?.*)?$/,
        loader: 'url-loader',
        options: {
          limit: 10000,
          name: utils.assetsPath('img/[name].[hash:7].[ext]')
        }
      },
      {
        test: /\.(mp4|webm|ogg|mp3|wav|flac|aac)(\?.*)?$/,
        loader: 'url-loader',
        options: {
          limit: 10000,
          name: utils.assetsPath('media/[name].[hash:7].[ext]')
        }
      },
      {
        test: /\.(woff2?|eot|ttf|otf)(\?.*)?$/,
        loader: 'url-loader',
        options: {
          limit: 10000,
          name: utils.assetsPath('fonts/[name].[hash:7].[ext]')
        }
      },
      {
        test:/\.css$/,
        use: ['vue-style-loader', 'css-loader'],
      }
    ]
  }
}

测试用例文件：

import Vue from 'vue'
import App from '../../src/App.vue'
import Crumbs from '../../src/components/Crumbs.vue'

import vueRouter from 'vue-router'

describe('test2 App.vue', ()=>{
  it('just test2',()=>{
    const defaultData = Crumbs.data()
    expect(defaultData.steps[0]).toBe('home')
  })
})