Migration Principles

This guide describes migration to Playwright Library and Playwright Test from Puppeteer. The APIs have similarities, but Playwright offers much more possibilities for web testing and cross-browser automation.

• Most Puppeteer APIs can be used as is
• The use of [ElementHandle] is discouraged, use [Locator] objects and web-first assertions instead.
• Playwright is cross-browser
• You probably don't need explicit wait

Cheat Sheet

page.waitForNavigation and page.waitForSelector remain, but in many cases will not be necessary due to auto-waiting.

The use of [ElementHandle] is discouraged, use [Locator] objects and web-first assertions instead.

Locators are the central piece of Playwright's auto-waiting and retry-ability. Locators are strict. This means that all operations on locators that imply some target DOM element will throw an exception if more than one element matches a given selector.

Examples

Automation example

Puppeteer:

const puppeteer = require('puppeteer');

(async () => {
  const browser = await puppeteer.launch();
  const page = await browser.newPage();
  await page.setViewport({ width: 1280, height: 800 });
  await page.goto('https://playwright.dev/', {
    waitUntil: 'networkidle2',
  });
  await page.screenshot({ path: 'example.png' });
  await browser.close();
})();

Line-by-line migration to Playwright:

const { chromium } = require('playwright'); // 1

(async () => {
  const browser = await chromium.launch();
  const page = await browser.newPage(); // 2
  await page.setViewportSize({ width: 1280, height: 800 }); // 3
  await page.goto('https://playwright.dev/', {
    waitUntil: 'networkidle', // 4
  });
  await page.screenshot({ path: 'example.png' });
  await browser.close();
})();

Migration highlights (see inline comments in the Playwright code snippet):

1. Each Playwright Library file has explicit import of chromium. Other browsers webkit or firefox can be used.
2. For browser state isolation, consider browser contexts
3. setViewport becomes setViewportSize
4. networkidle2 becomes networkidle. Please note that in most cases it is not useful, thanks to auto-waiting.

Test example

Puppeteer with Jest:

import puppeteer from 'puppeteer';

describe('Playwright homepage', () => {
  let browser;
  let page;

  beforeAll(async () => {
    browser = await puppeteer.launch();
    page = await browser.newPage();
  });

  it('contains hero title', async () => {
    await page.goto('https://playwright.dev/');
    await page.waitForSelector('.hero__title');
    const text = await page.$eval('.hero__title', e => e.textContent);
    expect(text).toContain('Playwright enables reliable end-to-end testing'); // 5
  });

  afterAll(() => browser.close());
});

Line-by-line migration to Playwright Test:

import { test, expect } from '@playwright/test'; // 1

test.describe('Playwright homepage', () => {
  test('contains hero title', async ({ page }) => { // 2, 3
    await page.goto('https://playwright.dev/');
    const titleLocator = page.locator('.hero__title'); // 4
    await expect(titleLocator).toContainText( // 5
        'Playwright enables reliable end-to-end testing'
    );
  });
});

1. Each Playwright Test file has explicit import of the test and expect functions
2. Test function is marked with async
3. Playwright Test is given a page as one of its parameters. This is one of the many useful fixtures in Playwright Test. Playwright Test creates an isolated [Page] object for each test. However, if you'd like to reuse a single [Page] object between multiple tests, you can create your own in [method: Test.beforeAll] and close it in [method: Test.afterAll].
4. Locator creation with [method: Page.locator] is one of the few methods that is sync.
5. Use assertions to verify the state instead of page.$eval().

Testing

To improve testing, it is advised to use Locators and web-first Assertions. See Writing Tests

It is common with Puppeteer to use page.evaluate() or page.$eval() to inspect an [ElementHandle] and extract the value of text content, attribute, class... Web-first Assertions offers several matchers for this purpose, it is more reliable and readable.

Playwright Test is our first-party recommended test runner to be used with Playwright. It provides several features like Page Object Model, parallelism, fixtures or reporters.

Playwright Test Super Powers

Once you're on Playwright Test, you get a lot!

• Full zero-configuration TypeScript support
• Run tests across all web engines (Chrome, Firefox, Safari) on any popular operating system (Windows, macOS, Ubuntu)
• Full support for multiple origins, (i)frames, tabs and contexts
• Run tests in isolation in parallel across multiple browsers
• Built-in test artifact collection

You also get all these ✨ awesome tools ✨ that come bundled with Playwright Test:

• Playwright Inspector
• Playwright Test Code generation
• Playwright Tracing for post-mortem debugging

Further Reading

Learn more about Playwright Test runner:

• Getting Started
• Fixtures
• Locators
• Assertions
• Auto-waiting

Source: docs/src/puppeteer-js.md