Playwright

What is Playwright?

Playwright is a modern, open-source framework for web automation and testing developed by Microsoft. It's designed to be fast, reliable, and capable, enabling developers to write tests that run across all major rendering engines: Chromium (powering Chrome and Edge), Firefox, and WebKit (powering Safari). Playwright supports multiple programming languages, including TypeScript, JavaScript, Python, .NET, and Java.

Key Features

• Cross-Browser and Cross-Platform: A single API to automate across Chromium, Firefox, and WebKit on Windows, macOS, and Linux.
• Auto-Waits: Playwright automatically waits for elements to be ready before interacting with them, which eliminates a common cause of flaky tests.
• Resilience and Reliability: Performs a variety of actionability checks on elements before interacting with them, leading to more stable tests.
• Parallel Test Execution: Supports running tests in parallel, which can significantly speed up test execution time.
• Browser Contexts: Uses browser contexts to create isolated, incognito-like sessions for each test, providing full test isolation with minimal overhead.
• Rich Tooling:
  • Codegen: A tool that records user interactions and generates test scripts.
  • Playwright Inspector: A debugging tool to step through test execution.
  • Trace Viewer: A tool that captures a detailed trace of test execution, including a screencast, DOM snapshots, and network requests.
• Mobile Emulation: Test how your web application behaves on different mobile devices.
• Network Interception: Intercept and mock network requests to test edge cases.

Getting Started (with Node.js)

To get started with Playwright, you can use npm or yarn to install it.

npm init playwright@latest

This command will create a playwright.config.ts file and some example tests.

Here's a simple example of a test that navigates to a website and takes a screenshot:

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

test('has title', async ({ page }) => {
  await page.goto('https://playwright.dev/');

  // Expect a title "to contain" a substring.
  await expect(page).toHaveTitle(/Playwright/);
});

Use Cases

• End-to-End Testing: Verify that all parts of a web application work together as expected.
• Cross-Browser Testing: Ensure that a web application functions consistently across different browsers.
• Web Scraping: Extract data from websites.
• Automating Repetitive Tasks: Automate any sequence of actions on a website.

Pros and Cons

Pros

• Fast and Reliable: Designed to be fast and to avoid flaky tests.
• Modern Feature Set: Includes features like auto-waits, network interception, and rich tooling.
• Great Developer Experience: The tooling (Codegen, Inspector, Trace Viewer) makes it easy to write and debug tests.
• Excellent Documentation: The official documentation is comprehensive and easy to follow.

Cons

• Newer than Selenium: Has a smaller community compared to Selenium, but it's growing rapidly.
• Focus on Modern Web: May not be the best choice for testing legacy web applications.

Playwright vs. Selenium

Playwright and Selenium are both powerful tools, but Playwright is generally considered more modern and easier to use.

• Playwright has a more modern feature set, better performance, and a better developer experience out of the box.
• Selenium has a larger community and a longer history, which means more resources and third-party integrations are available.