Testing lazy loaded image libraries

lazyimages_demos_test.js

/**
 * Copyright 2018 Google Inc. All rights reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 * @author ebidel@ (Eric Bidelman)
*/

const puppeteer = require('puppeteer');
const {spawnSync} = require('child_process');

const DEMO_LINKS = 'https://avgp.github.io/lazyloading-experiments/';

// https://github.com/GoogleChromeLabs/puppeteer-examples/blob/master/lazyimages_without_scroll_events.js
const TEST_SCRIPT = `${__dirname}/lazyimages_without_scroll_events.js`;

async function collectDemos(url) {
  const browser = await puppeteer.launch({headless: true});

  console.info(`Collecting demo links from ${url}...`);
  const page = await browser.newPage();
  await page.goto(url);

  const lis = await page.$$('#lazyloading-experiments + ul a');
  const demosUrls = await Promise.all(lis.map(async li => {
    const href = await li.getProperty('href');
    return href.jsonValue();
  }));

  await browser.close();

  return demosUrls;
}

(async() => {


const demosUrls = await collectDemos(DEMO_LINKS);

// Add a few more.
demosUrls.push('https://rawgit.com/GoogleChromeLabs/puppeteer-examples/master/html/lazyload.html'); // Should PASS.
demosUrls.push('https://css-tricks.com/examples/LazyLoading/'); // should FAIL.
demosUrls.push('http://dinbror.dk/blazy/'); // should FAIL.

console.info('Testing started...');
demosUrls.forEach((demo, i) => {
  console.info(`\nTesting ${demo}.`);
  const child = spawnSync('node', [TEST_SCRIPT, '-u', demo, '-o', `results${i}.html`], {
    // detached: true,
    stdio: 'inherit',
    shell: true,
  });
});

console.info('Testing complete...');

})();