regressify/.engine_scripts/puppet/overrideCSS.js

Visual regression tests support

const fs = require('fs');
const path = require('path');

module.exports = async (page, scenario) => {
  const cssOverridePath = scenario.cssOverridePath;

  if (!cssOverridePath) {
    return;
  } else if (!fs.existsSync(cssOverridePath)) {
    console.log('File not exist: ' + cssOverridePath);
    return;
  }

  const override = fs.readFileSync(cssOverridePath, 'utf-8');

  // inject arbitrary css to override styles
  await page.evaluate(`window._styleData = '${override}'`);
  await page.evaluate(() => {
    const style = document.createElement('style');
    style.type = 'text/css';
    const styleNode = document.createTextNode(window._styleData);
    style.appendChild(styleNode);
    document.head.appendChild(style);
  });

  console.log('BACKSTOP_TEST_CSS_OVERRIDE injected for: ' + scenario.label);
  // console.log(override);
};