Web Test Runner Chrome

Browser launcher for @web/test-runner. Looks for a locally installed instance of Chrome, and controls it using puppeteer-core. This avoids the postinstall step of puppeteer or playwright, speeding up installation of projects.

If you don't want to install Chrome globally, for example in a CI environment, you can use @web/test-runner-puppeeteer or @web/test-runner-playwright

See @web/test-runner for a default implementation and CLI for the test runner.

Usage

If you are using @web/test-runner, the chrome launcher is used by default. You can instantiate it yourself from the config to use on the advanced options.

Customizing launcher options

If you want to customize the puppeteer launcher options, you can add the browser launcher in the config.

You can find all possible launch options in the official documentation

const { chromeLauncher } = require('@web/test-runner-chrome');

module.exports = {
  browsers: [
    chromeLauncher({
      launchOptions: {
        headless: false,
        args: ['--some-flag'],
      },
    }),
  ],
};

Customizing page creation

You can use a custom function to create the puppeteer Page. You can use this for example to set up injecting scripts for environment variables or to expose functions to the browser to control the page.

const { chromeLauncher } = require('@web/test-runner-chrome');

module.exports = {
  browsers: [
    chromeLauncher({
      async createPage({ browser, config }) {
        const page = await browser.newPage();

        // expose websocket endpoint as an environment variable in the browser
        page.evaluateOnNewDocument(wsEndpoint => {
          window.__ENV__ = { wsEndpoint };
        }, browser.wsEndpoint());

        // expose a function in the browser, which calls a function on the
        // puppeteer page in NodeJS
        page.exposeFunction('puppeteerBringToFront', () => {
          page.bringToFront();
        });

        return page;
      },
    }),
  ],
};