Vue-cli 3 how to integrate karma?

Question

What problem does this feature solve? karma Unit Testing

What does the proposed API look like? Vue-cli 3 integration karma

Karma can't get the mode defined in vue-cli 3

Below is my karma.conf.js

const path = require('path')
const webpackConfig = require(path.join(process.cwd(), '/node_modules/@vue/cli-service/webpack.config.js'))

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

    basePath: '',

    frameworks: ['mocha', 'chai'],

    files: [
      'test/*.test.js'
    ],

    exclude: [
      'node_modules'
    ],

    preprocessors: {
      'test/*.test.js': ['webpack', 'sourcemap']
    },

    webpack: {
      ...webpackConfig,
      mode: 'production'
    },

    reporters: ['progress'],

    port: 9876,

    colors: true,

    logLevel: config.LOG_INFO,

    autoWatch: true,

    browsers: ['Chrome'],

    singleRun: false,

    concurrency: Infinity
  })
}