code: function startKarmaServer(isTddMode, isSaucelabs, done) {
    var karmaServer = require('karma').Server;
    var travis = process.env.TRAVIS;
  
    var config = {configFile: `${__dirname}/karma.conf.js`, singleRun: !isTddMode, autoWatch: isTddMode};
  
    if (travis) {
      config['reporters'] = ['dots'];
      config['browsers'] = ['Firefox'];
    }
  
    if (isSaucelabs) {
      config['reporters'] = ['dots', 'saucelabs'];
      config['browsers'] =
          ['SL_CHROME', 'SL_FIREFOX', 'SL_IE10', 'SL_IE11', 'SL_EDGE13', 'SL_EDGE14', 'SL_SAFARI9', 'SL_SAFARI10'];
  
      if (process.env.TRAVIS) {
        var buildId = `TRAVIS #${process.env.TRAVIS_BUILD_NUMBER} (${process.env.TRAVIS_BUILD_ID})`;
        config['sauceLabs'] = {build: buildId, tunnelIdentifier: process.env.TRAVIS_JOB_NUMBER};
        process.env.SAUCE_ACCESS_KEY = process.env.SAUCE_ACCESS_KEY.split('').reverse().join('');
      }
    }
  
    new karmaServer(config, done).start();
  }
docs: Testing