Webpack ES2015 Karma with Test coverage

karma.conf.js

/* eslint-env node */
var path = require('path');
var _ = require('lodash');
var here = require('path-here');

/**
 * Current Environment
 * @type {string}
 */
process.env.NODE_ENV = process.env.NODE_ENV || 'test';

/**
 * If tests are being run in DEBUG mode
 * @type {boolean}
 */
var debug = process.env.DEBUG === 'true';

/**
 * If tests are being run by Continuous Integration
 * @type {boolean}
 */
var ci = process.env.NODE_ENV === 'test:ci';

/**
 * Webpack configuration
 * @type {*|exports|module.exports}
 */
var webpackConfig = require('./webpack.config');
webpackConfig.entry = {};

module.exports = function(config) {
  config.set({
    basePath: './',
    frameworks: ['jasmine'],
    files: [
      'assets/js/vendor.js',
      'bower_components/angular-mocks/angular-mocks.js',
      './src/main.js',
      './src/**/*.spec.js'
    ],
    babelPreprocessor: {
      options: {
        presets: ['es2015'],
        sourceMap: 'inline'
      }
    },
    preprocessors: {
      './src/main.js': ['webpack', 'sourcemap'],
      './src/**/*.spec.js': ['webpack']
    },
    reporters: ['progress', 'coverage'],
    webpack: {
      devtool: 'inline-source-map',
      module: {
        loaders: webpackConfig.module.loaders,
        postLoaders: [
          {
            test: /\.js$/,
            exclude: /(__tests__|node_modules|bower_components)\//,
            loader: 'istanbul-instrumenter'
          }
        ]
      }
    },
    webpackMiddleware: {noInfo: true},
    coverageReporter: {
      reporters: [
        {type: 'html', dir: 'coverage/'},
        {type: 'lcov', dir: 'coverage/', subdir: '.'},
        {type: 'json', dir: 'coverage/', subdir: '.'},
        {type: 'text-summary'}
      ]
    },
    port: 9876,
    colors: true,
    logLevel: config.LOG_INFO,
    autoWatch: !ci,
    browsers: [debug ? 'Chrome' : 'PhantomJS2'],
    singleRun: ci,
    browserNoActivityTimeout: 180000
  });
};

webpack.config.js

var webpack = require('webpack');

module.exports = {
  entry: __dirname + '/src/main.js',

  stats: {
    colors: true,
    reasons: true
  },

  devtool: 'source-map',

  output: {
    path: './assets/js',
    filename: 'main.js'
  },

  module: {
    loaders: [
      {
        test: /\.js?$/,
        exclude: /(node_modules|bower_components)/,
        loader: 'babel',
        query: {
          presets: ['es2015'],
          plugins: ['transform-runtime']
        }
      },
      {
        test: /\.html$/,
        name: "templates",
        loader: 'raw!html-minify'
      }
    ]
  },

  'html-minify-loader': {
    empty: true,        // KEEP empty attributes
    cdata: true,        // KEEP CDATA from scripts
    comments: true     // KEEP comments
  }
};