Playwright Test Best Practices for Scalability

Table of Contents

• Introduction
• 1. Organize Your Test Suite
• 2. Optimize Test Execution
• 3. Features Comparison
• 4. Ensure Test Reliability
• 5. Maintain Performance
• 6. Integrate with CI/CD
• 7. Best Practices Checklist
• Conclusion

Introduction

As your test suite grows, maintaining its speed, reliability, and manageability becomes increasingly challenging. Playwright, with its robust features, is well-suited for scalable test automation. However, achieving scalability requires adopting best practices to ensure that your tests remain efficient and maintainable over time. In this post, we’ll discuss strategies for writing scalable Playwright tests, managing test data, and optimizing performance.

1. Organize Your Test Suite

a. Use the Page Object Model (POM)

The Page Object Model helps encapsulate page-specific locators and methods, making your tests cleaner and easier to maintain.

Example:

class LoginPage {
  constructor(page) {
    this.page = page;
    this.usernameField = '#username';
    this.passwordField = '#password';
    this.loginButton = '#login';
  }

  async login(username, password) {
    await this.page.fill(this.usernameField, username);
    await this.page.fill(this.passwordField, password);
    await this.page.click(this.loginButton);
  }
}

module.exports = { LoginPage };

b. Group Tests Logically

Organize tests into folders and use descriptive names to make them easy to navigate.

/tests
  /authentication
    login.spec.js
    logout.spec.js
  /user-management
    create-user.spec.js
    delete-user.spec.js

2. Optimize Test Execution

a. Run Tests in Parallel

Playwright supports parallel test execution out of the box. Configure the number of workers in playwright.config.ts:

import { defineConfig } from '@playwright/test';

export default defineConfig({
  workers: 4,
});

b. Use Sharding for Large Suites

Divide your test suite across multiple machines to reduce execution time:

npx playwright test --shard=1/2  # Run first half
npx playwright test --shard=2/2  # Run second half

c. Leverage Test Retries

Retry failed tests to handle intermittent issues:

export default defineConfig({
  retries: 2,
});

3. Manage Test Data Effectively

a. Use API Calls for Setup and Cleanup

Instead of relying on UI interactions, use API calls to set up and clean up test data. This reduces execution time and improves reliability.

Example:

await request.post('/api/users', { data: { username: 'testuser' } });

b. Isolate Test Data

Ensure that each test runs independently by creating unique test data. Use utilities like UUIDs to avoid conflicts.

const uniqueUsername = `user_${Date.now()}`;

c. Use Fixtures for Reusable Data

Define reusable test data and setup logic with fixtures:

import { test as base } from '@playwright/test';

export const test = base.extend({
  testUser: async ({}, use) => {
    const user = await createTestUser();
    await use(user);
    await deleteTestUser(user.id);
  },
});

4. Ensure Test Reliability

a. Avoid Hard-Coded Waits

Replace page.waitForTimeout with robust waiting strategies like page.waitForSelector or Playwright’s built-in auto-waiting.

await page.waitForSelector('#dashboard');

b. Handle Flaky Tests

Use tools like Playwright’s trace viewer to debug flaky tests:

npx playwright show-trace trace.zip

c. Mock Network Requests

Isolate tests from backend dependencies by mocking network requests:

await page.route('**/api/data', route => {
  route.fulfill({ status: 200, body: JSON.stringify({ key: 'value' }) });
});

5. Maintain Performance

a. Run Tests Headless in CI/CD

Running tests in headless mode reduces resource usage and speeds up execution:

const browser = await chromium.launch({ headless: true });

b. Limit Browser Instances

Reuse browser contexts instead of launching new instances for every test:

const context = await browser.newContext();
const page = await context.newPage();

c. Profile Test Performance

Use the tracing API to identify slow test steps:

await page.tracing.start({ screenshots: true, snapshots: true });
await page.goto('https://example.com');
await page.tracing.stop({ path: 'trace.zip' });

6. Integrate with CI/CD

a. Use Playwright’s GitHub Actions

Leverage Playwright’s prebuilt GitHub Actions for seamless CI/CD integration:

jobs:
  test:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v3
      - uses: microsoft/playwright-github-action@v1

b. Generate and Publish Reports

Configure Playwright to generate HTML reports and upload them as artifacts:

export default defineConfig({
  reporter: [['html', { outputFolder: 'playwright-report' }]],
});

7. Best Practices Checklist

1. Use POM to organize locators and actions.
2. Run tests in parallel and use sharding for scalability.
3. Set up test data with APIs instead of UI interactions.
4. Use robust waiting strategies and avoid hard-coded waits.
5. Mock network requests to isolate tests.
6. Profile and optimize test performance regularly.
7. Integrate tests with CI/CD pipelines for continuous feedback.

Conclusion

Building a scalable Playwright test suite requires a combination of thoughtful architecture, optimized execution, and effective data management. By following these best practices, you can ensure that your tests remain fast, reliable, and easy to maintain as your application grows.

What are your favorite tips for scaling Playwright tests? Share them in the comments below!