karma.conf.js

// Karma configuration
// Generated on Wed Jun 20 2018 16:46:14 GMT+0200 (CEST)
const webpackConfig = require('./webpack.config.js');

module.exports = function (config) {
  config.set({
    basePath: '',
    frameworks: ['mocha', 'chai', 'sinon'],
    files: [
      // we use 1 bundle for testing
      { pattern: 'lib/test/index.js' },
    ],
    exclude: ['**/embed.js'],
    preprocessors: {
      // the bundle goes through webpack, and will emit (inline) source maps, which karma needs to read again
      'lib/test/index.js': ['webpack', 'sourcemap'],
    },
    webpack: {
      module: {
        rules: webpackConfig[0].module.rules,
      },
      // source mapping without inline does not seem to work
      devtool: 'inline-source-map',
      mode: 'development',
      resolve: {
        extensions: ['.js'],
      },
    },
    reporters: ['progress', 'mocha'],
    port: 9876,
    colors: true,
    // possible values: config.LOG_DISABLE || config.LOG_ERROR || config.LOG_WARN || config.LOG_INFO || config.LOG_DEBUG
    logLevel: config.LOG_INFO,
    autoWatch: true,
    // available browser launchers: https://npmjs.org/browse/keyword/karma-launcher
    browsers: ['ChromeHeadless'],
    customLauncher: {
      ChromeHeadless: {
        base: 'ChromeHeadless',
        flags: ['--headless', '--remote-debugging-port=9222'],
      },
    },
    // if true, Karma captures browsers, runs the tests and exits
    singleRun: true,
    // how many browser should be started simultaneous
    concurrency: Infinity,
  });
};