Tilted sphere with longitudinal stripes Modern Web Guides Docs Blog

Browser Launchers: Chrome

Runs tests with a locally installed instance of Chrome and controls it using puppeteer-core. This avoids the post-install step of puppeteer or playwright, speeding up the installation of projects.

Use Puppeteer if you don't want to install Chrome globally, for example in a CI environment.

Usage

When using @web/test-runner regularly, the chrome launcher is installed and used by default.

For other projects you can install the browser launcher by running:

@web/test-runner-chrome

And included in your config:

import { chromeLauncher } from '@web/test-runner-chrome';

export default {
  browsers: [chromeLauncher()],
};

Concurrency

You can override the concurrency of this specific browser launcher

import { chromeLauncher } from '@web/test-runner-chrome';

export default {
  browsers: [chromeLauncher({ concurrency: 1 })],
};

Customizing launch 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

import { chromeLauncher } from '@web/test-runner-chrome';

export default {
  browsers: [
    chromeLauncher({
      launchOptions: {
        executablePath: '/path/to/executable',
        headless: false,
        devtools: true,
        args: ['--some-flag'],
      },
    }),
  ],
};

Customizing browser context and page

You can customize the way the browser context or puppeteer page is created. This allows configuring the test environment. Check the official documentation for all API options.

import { chromeLauncher } from '@web/test-runner-chrome';

export default {
  browsers: [
    chromeLauncher({
      createBrowserContext: ({ browser, config }) => browser.defaultBrowserContext(),
      createPage: ({ context, config }) => context.newPage(),
    }),
  ],
};

Some examples:

Emulate mobile browser

import { chromeLauncher, devices } from '@web/test-runner-chrome';

export default {
  browsers: [
    chromeLauncher({
      async createPage({ context }) {
        const page = await context.newPage();
        page.emulate(devices['Pixel 2']);
        return page;
      },
    }),
  ],
};

Grant browser permissions

import { chromeLauncher } from '@web/test-runner-chrome';

export default {
  browsers: [
    chromeLauncher({
      async createBrowserContext({ browser }) {
        // use default browser context
        const context = browser.defaultBrowserContext();

        // or create a new browser context if necessary
        // const context = await browser.createIncognitoBrowserContext()

        // grant the permissions
        await context.overridePermissions('http://localhost:8000/', ['geolocation']);
        return context;
      },
    }),
  ],
};