demoComponent.js

import { expect } from 'chai';

export default function(browser) {
  return browser.component({
    fetchTODOsButton() {
      return this.find('button');
    },

    loadingBar() {
      return this.find('.loading', {text: 'Loading...'});
    },

    async expectTODOs(...expectedTodos) {
      var actualTodos = (await this.find('ul li').elements())
        .map(e => e.innerText);

      expect(actualTodos.sort()).to.eql(expectedTodos.sort());
    }
  });
});

demoComponentImportedSpec.js

import createBrowser from 'browser-monkey/create';
import pageHelper from './pageHelper';

var browser, page;

beforeEach(() => {
  browser = createBrowser(document.body);
  page = pageHelper(browser);
});

it('allows user to fetch todos', async () => {
  await page.fetchTODOsButton().click();
  await page.loadingBar().shouldExist();
  await page.expectTODOs('one', 'two');
});

demoComponentSpec.js

import createBrowser from 'browser-monkey/create';
import pageHelper from './pageHelper';

var browser, page;

beforeEach(() => {
  browser = createBrowser(document.body);
  page = pageHelper(browser);
});

it('allows user to fetch todos', async () => {
  await page.fetchTODOsButton().click();
  await page.loadingBar().shouldExist();
  await page.expectTODOs('one', 'two');
});

demoSpec.js

import createBrowser from 'browser-monkey/create';
var browser;

beforeEach(() => {
  browser = createBrowser(document.body);
});

it('allows user to fetch todos', async () => {
  // click button
  await browser.find('button').click();
  
  // observe "Loading..."
  await browser.find('.loading', {text: 'Loading...'}).shouldExist();

  // collect results from DOM
  let actualTodos = (await browser.find('ul li').elements())
    .map(e => e.innerText);

  // assert results
  expect(actualTodos.sort()).to.eql(['one', 'two'].sort());
});

karma.conf.js

module.exports = function(config) {
  config.set({
    frameworks: ['browserify', 'mocha'],
    files: [
      'test/**/*Spec.js'
    ],
    preprocessors: {
      'test/**/*.js': ['browserify']
    },
    browserify: {
      debug: true,
      transform: ['babelify'],
      extensions: ['.jsx']
    },
  })
}

package.json

...  
  "scripts": {
    "test-karma": "karma start --single-run",
    "test-electron": "electron-mocha --renderer --compilers js:babel-core/register test/**/*Spec.js",
    "test-vdom": "mocha --compilers js:babel-core/register test/**/*Spec.js"
  },
...