karma.conf.js

module.exports = function (config) {
  config.set({
    ...
    plugins: [
      ...
      require('karma-coverage-istanbul-reporter'), // <- Add plugin
      require('karma-junit-reporter'), // <- Add plugin
      ...
    ],
    ...
    ...
    browsers: ['Chrome', 'PhantomJS'], // <- Add browser
    ...
  });
};