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Playwright vs Selenium

When considering automated testing tools for web applications, the choice between Playwright and Selenium is common. Both tools offer robust capabilities, but they cater to different needs and expertise levels. This article provides a detailed comparison to help you decide which solution is best for your project or organization.

Playwright is a relatively new browser automation framework that has gained popularity due to its modern approach to web testing. It supports multiple programming languages, but it is particularly well-suited for JavaScript and TypeScript users.

• Out-of-the-box Test Framework: Playwright comes bundled with Playwright Test, providing a comprehensive test automation framework that handles test execution, reporting, assertions, and more.
• Auto-Wait Mechanism: Playwright intelligently waits for elements to be ready before interacting with them, reducing the need for manual wait statements.
• Cross-Browser Testing: It supports Chromium, Firefox, and WebKit, making it useful for testing across different browsers.
• Parallel Execution: Built-in support for running tests in parallel to speed up execution time.
• Trace Viewer: A powerful debugging tool that records test execution, allowing you to inspect the behavior and identify issues.
• Headless Mode: Ability to run tests in headless mode for faster execution and CI/CD pipelines.

1. Install Playwright using npm:

   npm install --save-dev playwright
   

2. Set up a test script using @playwright/test:

   const { test, expect } = require('@playwright/test');
   
   test('example test', async ({ page }) => {
     await page.goto('<https://example.com>');
     const title = await page.title();
     expect(title).toBe('Example Domain');
   });
   

3. Run the test with the Playwright CLI:

   npx playwright test
   

Selenium has been a mainstay in browser automation for over a decade. It is widely used across the industry and supports multiple languages, including Java, Python, C#, and JavaScript. Selenium is a browser automation tool rather than a full-fledged testing framework, which means you’ll need to add additional libraries for assertions, reporting, and parallel test execution.

• Multi-Language Support: Selenium supports many programming languages, making it flexible for teams with diverse tech stacks.
• Cross-Browser Testing: It works with all major browsers, including Chrome, Firefox, Safari, and Edge.
• WebDriver Protocol: Selenium uses the WebDriver protocol, which is a standard for browser automation.
• Support for Real Devices: It integrates well with cloud services for testing on real devices.
• Large Ecosystem: There are many plugins, libraries, and resources available for Selenium.

Here’s how to run a Selenium test in NodeJS

1. Install Selenium WebDriver

   You can add Selenium WebDriver to your project using NPM:

   npm install selenium-webdriver
   

   Selenium WebDriver is the library that allows your tests to interact with browsers.

1. Import the Selenium WebDriver Module

   In your test file (e.g., test.js), import the selenium-webdriver package:

   const { Builder, By, until } = require('selenium-webdriver');
   

2. Set Up the Browser Driver

   Use the Builder to configure your test environment. Here is a simple example:

   async function exampleTest() {
     // Initialize a new browser instance
     let driver = await new Builder().forBrowser('chrome').build();
   
     try {
       // Navigate to a website
       await driver.get('https://www.example.com');
   
       // Perform actions or assertions
       let title = await driver.getTitle();
       console.log('Page Title:', title);
   
       // Find an element and interact with it
       let element = await driver.findElement(By.name('exampleInput'));
       await element.sendKeys('Test Input');
   
       // Wait for some condition, if necessary
       await driver.wait(until.titleIs('Expected Title'), 5000);
     } finally {
       // Clean up and close the browser
       await driver.quit();
     }
   }
   
   // Run the test
   exampleTest();
   

To run your test, execute node test.js in your terminal

This command launches a browser, performs the specified actions, and then closes the browser. You should see any console output you added, such as the page title.

While Playwright and Selenium are both used for similar roles as test automation. And both are focused on operating a browser automatically, the difference in their backgrounds, core userbase, and ages show up in a number of implementation details.

Here’s a test that simulates a user logging in and loading recent transactions. The automation then takes a screenshot.

const { Builder, By, until } = require('selenium-webdriver');
const fs = require('fs');

async function loginAndCaptureScreenshot() {
  // Initialize the browser driver
  let driver = await new Builder().forBrowser('chrome').build();

  try {
    // Step 1: Navigate to the login page
    await driver.get('https://www.example-service.com/login');

    // Step 2: Enter login credentials
    await driver.findElement(By.id('username')).sendKeys('your-username');
    await driver.findElement(By.id('password')).sendKeys('your-password');

    // Step 3: Click the login button
    await driver.findElement(By.id('login-button')).click();

    // Step 4: Wait until the transactions page is loaded
    await driver.wait(until.elementLocated(By.id('recent-transactions')), 10000);

    // Step 5: Load recent transactions
    let transactionsElement = await driver.findElement(By.id('recent-transactions'));

    // Verify transactions are visible (optional)
    let isDisplayed = await transactionsElement.isDisplayed();
    console.log('Transactions loaded:', isDisplayed);

    // Step 6: Take a screenshot
    let screenshot = await driver.takeScreenshot();
    fs.writeFileSync('screenshot.png', screenshot, 'base64');
    console.log('Screenshot taken and saved as screenshot.png');

  } catch (error) {
    console.error('An error occurred:', error);
  } finally {
    // Step 7: Close the browser
    await driver.quit();
  }
}

// Run the test
loginAndCaptureScreenshot();

Here’s the same test in Playwright:

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

async function loginAndCaptureScreenshot() {
    // Step 1: Navigate to the login page
    await page.goto('https://www.example-service.com/login');
    
    // Step 2: Enter login credentials
	  await page.getByLabel('Username or email address').fill('username');
	  await page.getByLabel('Password').fill('password');
	  
    // Step 3: Click the login button
	  await page.getByRole('button', { name: 'Sign in' }).click();
	  
	  // Step 4: Click recent transactions
	  await page.getByLabel('Transactions').click()
	  
	  // Step 5: Take a screenshot
	  await page.screenshot({ path: 'screenshot.png', fullPage: true });
}

// Run the test
loginAndCaptureScreenshot();

Some key differences in the two examples:

• Playwright uses modern css locators rather than finding by ID or class. ID and class can shift on an element when all that’s happening is a visual refresh of the site. We don’t want our tests to break in this situation!
• Playwright includes auto-waiting, so there’s no need to add manual timeouts to our code.

Pros: Easy to get started, built-in test framework, faster execution, modern architecture, better support for JavaScript/TypeScript. Cons: Fewer legacy languages supported (e.g. C), limited real device testing.

Pros: Established tool with a large community, supports many languages, better integration with real device testing. Cons: More setup required, slower execution, higher learning curve for productivity.

• If you’re starting a new project and want fast productivity.
• If your team is experienced with JavaScript or TypeScript.
• If you need built-in features like auto-waiting, test recording, and API testing.

• If you’re joining an established project that already uses Selenium.
• If you require deep device simulation

If you’re starting a new project, you want to use Playwright. You’ll get exposure to JS or Typescript, plug in to a great existing community, write tests and other automations faster, and your tests will be more consistent and reliable. You can adopt Playwright without needing to become a “Playwright specialist” and the skills you learn will encourage solid front-end engineering and language skills in other areas.

If you’re already using Selenium, it’s a framework with a lot of strengths! All other factors being equal, you don’t need to rip out your Selenium workflow just to adopt Playwright.

Engineers building testing and automation have more options than ever, and they can simulate a broader range of user actions with great tool suites. For now, our pick for new projects is Playwright, and we’re excited to see what new features are added to the project in the coming years.