playwright-testing

SKILL.md

Playwright E2E Testing Skill

For end-to-end testing of web applications with Playwright - cross-browser, fast, reliable.

Sources: Playwright Best Practices | Playwright Docs | Better Stack Guide

Setup

Installation

# New project
npm init playwright@latest

Existing project

npm install -D @playwright/test
npx playwright install

### Configuration

```typescript
// playwright.config.ts
import { defineConfig, devices } from '@playwright/test';

export default defineConfig({
  testDir: './e2e',
  fullyParallel: true,
  forbidOnly: !!process.env.CI,
  retries: process.env.CI ? 2 : 0,
  workers: process.env.CI ? 1 : undefined,
  reporter: [
    ['html'],
    ['list'],
    process.env.CI ? ['github'] : ['line'],
  ],

  use: {
    baseURL: process.env.BASE_URL || 'http://localhost:3000',
    trace: 'on-first-retry',
    screenshot: 'only-on-failure',
    video: 'retain-on-failure',
  },

  projects: [
    // Auth setup - runs once before all tests
    { name: 'setup', testMatch: /.*\.setup\.ts/ },

    {
      name: 'chromium',
      use: { ...devices['Desktop Chrome'] },
      dependencies: ['setup'],
    },
    {
      name: 'firefox',
      use: { ...devices['Desktop Firefox'] },
      dependencies: ['setup'],
    },
    {
      name: 'webkit',
      use: { ...devices['Desktop Safari'] },
      dependencies: ['setup'],
    },
    // Mobile viewports
    {
      name: 'mobile-chrome',
      use: { ...devices['Pixel 5'] },
      dependencies: ['setup'],
    },
    {
      name: 'mobile-safari',
      use: { ...devices['iPhone 12'] },
      dependencies: ['setup'],
    },
  ],

  // Start dev server before tests
  webServer: {
    command: 'npm run dev',
    url: 'http://localhost:3000',
    reuseExistingServer: !process.env.CI,
    timeout: 120 * 1000,
  },
});

Project Structure

project/
├── e2e/
│   ├── fixtures/
│   │   ├── auth.fixture.ts      # Auth fixtures
│   │   └── test.fixture.ts      # Extended test with fixtures
│   ├── pages/
│   │   ├── base.page.ts         # Base page object
│   │   ├── login.page.ts        # Login page object
│   │   ├── dashboard.page.ts    # Dashboard page object
│   │   └── index.ts             # Export all pages
│   ├── tests/
│   │   ├── auth.spec.ts         # Auth tests
│   │   ├── dashboard.spec.ts    # Dashboard tests
│   │   └── checkout.spec.ts     # Checkout flow tests
│   ├── utils/
│   │   ├── helpers.ts           # Test helpers
│   │   └── test-data.ts         # Test data factories
│   └── auth.setup.ts            # Global auth setup
├── playwright.config.ts
└── .auth/                        # Stored auth state (gitignored)

Locator Strategy (Priority Order)

Use locators that mirror how users interact with the page:

// ✅ BEST: Role-based (accessible, resilient)
page.getByRole('button', { name: 'Submit' })
page.getByRole('textbox', { name: 'Email' })
page.getByRole('link', { name: 'Sign up' })
page.getByRole('heading', { name: 'Welcome' })

// ✅ GOOD: User-facing text
page.getByLabel('Email address')
page.getByPlaceholder('Enter your email')
page.getByText('Welcome back')
page.getByTitle('Profile settings')

// ✅ GOOD: Test IDs (stable, explicit)
page.getByTestId('submit-button')
page.getByTestId('user-avatar')

// ⚠️ AVOID: CSS selectors (brittle)
page.locator('.btn-primary')
page.locator('#submit')

// ❌ NEVER: XPath (extremely brittle)
page.locator('//div[@class="container"]/button[1]')

Chaining Locators

// Narrow down to specific section
const form = page.getByRole('form', { name: 'Login' });
await form.getByRole('textbox', { name: 'Email' }).fill('user@example.com');
await form.getByRole('button', { name: 'Submit' }).click();

// Filter within a list
const productCard = page.getByTestId('product-card')
  .filter({ hasText: 'Pro Plan' });
await productCard.getByRole('button', { name: 'Buy' }).click();

Page Object Model

Base Page

// e2e/pages/base.page.ts
import { Page, Locator } from '@playwright/test';

export abstract class BasePage {
  constructor(protected page: Page) {}

  async navigate(path: string = '/') {
    await this.page.goto(path);
  }

  async waitForPageLoad() {
    await this.page.waitForLoadState('networkidle');
  }

  // Common elements
  get header() {
    return this.page.getByRole('banner');
  }

  get footer() {
    return this.page.getByRole('contentinfo');
  }

  // Common actions
  async clickNavLink(name: string) {
    await this.header.getByRole('link', { name }).click();
  }
}

Page Implementation

// e2e/pages/login.page.ts
import { Page, expect } from '@playwright/test';
import { BasePage } from './base.page';

export class LoginPage extends BasePage {
  readonly emailInput: Locator;
  readonly passwordInput: Locator;
  readonly submitButton: Locator;
  readonly errorMessage: Locator;

  constructor(page: Page) {
    super(page);
    this.emailInput = page.getByLabel('Email');
    this.passwordInput = page.getByLabel('Password');
    this.submitButton = page.getByRole('button', { name: 'Sign in' });
    this.errorMessage = page.getByRole('alert');
  }

  async goto() {
    await this.navigate('/login');
  }

  async login(email: string, password: string) {
    await this.emailInput.fill(email);
    await this.passwordInput.fill(password);
    await this.submitButton.click();
  }

  async expectError(message: string) {
    await expect(this.errorMessage).toContainText(message);
  }

  async expectLoggedIn() {
    await expect(this.page).toHaveURL(/.*dashboard/);
  }
}

// e2e/pages/dashboard.page.ts
import { Page, Locator, expect } from '@playwright/test';
import { BasePage } from './base.page';

export class DashboardPage extends BasePage {
  readonly welcomeHeading: Locator;
  readonly userMenu: Locator;
  readonly logoutButton: Locator;

  constructor(page: Page) {
    super(page);
    this.welcomeHeading = page.getByRole('heading', { name: /welcome/i });
    this.userMenu = page.getByTestId('user-menu');
    this.logoutButton = page.getByRole('button', { name: 'Logout' });
  }

  async goto() {
    await this.navigate('/dashboard');
  }

  async logout() {
    await this.userMenu.click();
    await this.logoutButton.click();
  }

  async expectWelcome(name: string) {
    await expect(this.welcomeHeading).toContainText(name);
  }
}

Export All Pages

// e2e/pages/index.ts
export { BasePage } from './base.page';
export { LoginPage } from './login.page';
export { DashboardPage } from './dashboard.page';

Authentication

Global Auth Setup

// e2e/auth.setup.ts
import { test as setup, expect } from '@playwright/test';
import path from 'path';

const authFile = path.join(__dirname, '../.auth/user.json');

setup('authenticate', async ({ page }) => {
  // Go to login page
  await page.goto('/login');

  // Login with test credentials
  await page.getByLabel('Email').fill(process.env.TEST_USER_EMAIL!);
  await page.getByLabel('Password').fill(process.env.TEST_USER_PASSWORD!);
  await page.getByRole('button', { name: 'Sign in' }).click();

  // Wait for auth to complete
  await expect(page).toHaveURL(/.*dashboard/);

  // Save auth state for reuse
  await page.context().storageState({ path: authFile });
});

Using Auth in Tests

// playwright.config.ts
export default defineConfig({
  projects: [
    { name: 'setup', testMatch: /.*\.setup\.ts/ },
    {
      name: 'chromium',
      use: {
        ...devices['Desktop Chrome'],
        storageState: '.auth/user.json',
      },
      dependencies: ['setup'],
    },
  ],
});

Tests Without Auth

// e2e/tests/public.spec.ts
import { test } from '@playwright/test';

// Override to skip auth
test.use({ storageState: { cookies: [], origins: [] } });

test('homepage loads for anonymous users', async ({ page }) => {
  await page.goto('/');
  await expect(page.getByRole('heading', { name: 'Welcome' })).toBeVisible();
});

Writing Tests

Basic Test Structure

// e2e/tests/auth.spec.ts
import { test, expect } from '@playwright/test';
import { LoginPage } from '../pages';

test.describe('Authentication', () => {
  test.beforeEach(async ({ page }) => {
    // Skip stored auth for login tests
    await page.context().clearCookies();
  });

  test('successful login redirects to dashboard', async ({ page }) => {
    const loginPage = new LoginPage(page);

    await loginPage.goto();
    await loginPage.login('user@example.com', 'password123');
    await loginPage.expectLoggedIn();
  });

  test('invalid credentials show error', async ({ page }) => {
    const loginPage = new LoginPage(page);

    await loginPage.goto();
    await loginPage.login('wrong@example.com', 'wrongpass');
    await loginPage.expectError('Invalid email or password');
  });

  test('empty form shows validation errors', async ({ page }) => {
    const loginPage = new LoginPage(page);

    await loginPage.goto();
    await loginPage.submitButton.click();

    await expect(page.getByText('Email is required')).toBeVisible();
    await expect(page.getByText('Password is required')).toBeVisible();
  });
});

User Flow Tests

// e2e/tests/checkout.spec.ts
import { test, expect } from '@playwright/test';

test.describe('Checkout Flow', () => {
  test('complete purchase flow', async ({ page }) => {
    // 1. Browse products
    await page.goto('/products');
    await page.getByTestId('product-card')
      .filter({ hasText: 'Pro Plan' })
      .getByRole('button', { name: 'Add to cart' })
      .click();

    // 2. View cart
    await page.getByRole('link', { name: 'Cart' }).click();
    await expect(page.getByText('Pro Plan')).toBeVisible();
    await expect(page.getByTestId('cart-total')).toContainText('$29.99');

    // 3. Checkout
    await page.getByRole('button', { name: 'Checkout' }).click();

    // 4. Fill payment (use Stripe test card)
    const stripeFrame = page.frameLocator('iframe[name*="stripe"]');
    await stripeFrame.getByPlaceholder('Card number').fill('4242424242424242');
    await stripeFrame.getByPlaceholder('MM / YY').fill('12/30');
    await stripeFrame.getByPlaceholder('CVC').fill('123');

    // 5. Complete purchase
    await page.getByRole('button', { name: 'Pay now' }).click();

    // 6. Verify success
    await expect(page).toHaveURL(/.*success/);
    await expect(page.getByRole('heading', { name: 'Thank you' })).toBeVisible();
  });
});

Assertions

Web-First Assertions (Auto-Wait)

// ✅ These wait and retry automatically
await expect(page.getByRole('button')).toBeVisible();
await expect(page.getByRole('button')).toBeEnabled();
await expect(page.getByRole('button')).toHaveText('Submit');
await expect(page).toHaveURL('/dashboard');
await expect(page).toHaveTitle(/Dashboard/);

// ❌ Avoid manual waits
await page.waitForTimeout(3000);  // NEVER do this

Soft Assertions

// Continue test even if assertion fails
await expect.soft(page.getByTestId('price')).toHaveText('$29.99');
await expect.soft(page.getByTestId('stock')).toHaveText('In Stock');

// Fail at end if any soft assertions failed

Common Assertions

// Visibility
await expect(locator).toBeVisible();
await expect(locator).toBeHidden();
await expect(locator).toBeAttached();

// Text content
await expect(locator).toHaveText('exact text');
await expect(locator).toContainText('partial');
await expect(locator).toHaveValue('input value');

// State
await expect(locator).toBeEnabled();
await expect(locator).toBeDisabled();
await expect(locator).toBeChecked();
await expect(locator).toBeFocused();

// Count
await expect(locator).toHaveCount(5);

// Page
await expect(page).toHaveURL('/dashboard');
await expect(page).toHaveTitle('Dashboard | App');
await expect(page).toHaveScreenshot('dashboard.png');

Mocking & Network

Mock API Responses

test('shows error when API fails', async ({ page }) => {
  // Mock API to return error
  await page.route('**/api/users', (route) => {
    route.fulfill({
      status: 500,
      body: JSON.stringify({ error: 'Server error' }),
    });
  });

  await page.goto('/users');
  await expect(page.getByText('Failed to load users')).toBeVisible();
});

test('displays user data from API', async ({ page }) => {
  // Mock successful response
  await page.route('**/api/users', (route) => {
    route.fulfill({
      status: 200,
      contentType: 'application/json',
      body: JSON.stringify([
        { id: 1, name: 'John Doe', email: 'john@example.com' },
        { id: 2, name: 'Jane Doe', email: 'jane@example.com' },
      ]),
    });
  });

  await page.goto('/users');
  await expect(page.getByText('John Doe')).toBeVisible();
  await expect(page.getByText('Jane Doe')).toBeVisible();
});

Wait for API Calls

test('submits form and shows success', async ({ page }) => {
  await page.goto('/contact');

  // Fill form
  await page.getByLabel('Name').fill('John');
  await page.getByLabel('Email').fill('john@example.com');
  await page.getByLabel('Message').fill('Hello!');

  // Wait for API call on submit
  const responsePromise = page.waitForResponse('**/api/contact');
  await page.getByRole('button', { name: 'Send' }).click();

  const response = await responsePromise;
  expect(response.status()).toBe(200);

  await expect(page.getByText('Message sent!')).toBeVisible();
});

Visual Testing

// Full page screenshot
await expect(page).toHaveScreenshot('homepage.png');

// Element screenshot
await expect(page.getByTestId('chart')).toHaveScreenshot('chart.png');

// With options
await expect(page).toHaveScreenshot('dashboard.png', {
  maxDiffPixels: 100,
  mask: [page.getByTestId('timestamp')], // Ignore dynamic content
});

CI/CD Integration

GitHub Actions

# .github/workflows/e2e.yml
name: E2E Tests

on:
  push:
    branches: [main]
  pull_request:
    branches: [main]

jobs:
  test:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4

      - uses: actions/setup-node@v4
        with:
          node-version: 20
          cache: 'npm'

      - name: Install dependencies
        run: npm ci

      - name: Install Playwright browsers
        run: npx playwright install --with-deps chromium

      - name: Run E2E tests
        run: npx playwright test --project=chromium
        env:
          BASE_URL: ${{ secrets.STAGING_URL }}
          TEST_USER_EMAIL: ${{ secrets.TEST_USER_EMAIL }}
          TEST_USER_PASSWORD: ${{ secrets.TEST_USER_PASSWORD }}

      - uses: actions/upload-artifact@v4
        if: failure()
        with:
          name: playwright-report
          path: playwright-report/
          retention-days: 7

Run Specific Tests

# Run all tests
npx playwright test

# Run specific file
npx playwright test e2e/tests/auth.spec.ts

# Run tests with tag
npx playwright test --grep @critical

# Run in headed mode (debug)
npx playwright test --headed

# Run specific browser
npx playwright test --project=chromium

# Debug mode
npx playwright test --debug

# Show HTML report
npx playwright show-report

Test Data

Factories

// e2e/utils/test-data.ts
import { faker } from '@faker-js/faker';

export const createUser = (overrides = {}) => ({
  email: faker.internet.email(),
  password: faker.internet.password({ length: 12 }),
  name: faker.person.fullName(),
  ...overrides,
});

export const createProduct = (overrides = {}) => ({
  name: faker.commerce.productName(),
  price: faker.commerce.price({ min: 10, max: 100 }),
  description: faker.commerce.productDescription(),
  ...overrides,
});

Environment Variables

# .env.test
BASE_URL=http://localhost:3000
TEST_USER_EMAIL=test@example.com
TEST_USER_PASSWORD=testpassword123

Debugging

Trace Viewer

// Enable in config for failures
use: {
  trace: 'on-first-retry',
}

// View traces
npx playwright show-trace trace.zip

Debug Mode

# Step through test
npx playwright test --debug

# Pause at specific point
await page.pause();  // In test code

VS Code Extension

Install "Playwright Test for VS Code" for:

Run tests from editor

Debug with breakpoints

Pick locators visually

Watch mode

Dead Link Detection (REQUIRED)

Every project MUST include dead link detection tests. Run these on every deployment.

Link Validator Test

// e2e/tests/links.spec.ts
import { test, expect } from '@playwright/test';

const PAGES_TO_CHECK = ['/', '/about', '/pricing', '/blog', '/contact'];

test.describe('Dead Link Detection', () => {
  for (const pagePath of PAGES_TO_CHECK) {
    test(`no dead links on ${pagePath}`, async ({ page, request }) => {
      await page.goto(pagePath);

      // Get all links on the page
      const links = await page.locator('a[href]').all();
      const hrefs = await Promise.all(
        links.map(link => link.getAttribute('href'))
      );

      // Filter to internal and absolute external links
      const uniqueLinks = [...new Set(hrefs.filter(Boolean))] as string[];

      for (const href of uniqueLinks) {
        // Skip mailto, tel, and anchor links
        if (href.startsWith('mailto:') || href.startsWith('tel:') || href.startsWith('#')) {
          continue;
        }

        // Build full URL
        const url = href.startsWith('http') ? href : new URL(href, page.url()).href;

        // Check link status
        const response = await request.get(url, {
          timeout: 10000,
          ignoreHTTPSErrors: true,
        });

        expect(
          response.ok(),
          `Dead link found on ${pagePath}: ${href} returned ${response.status()}`
        ).toBeTruthy();
      }
    });
  }
});

Comprehensive Link Crawler

// e2e/tests/site-links.spec.ts
import { test, expect, Page, APIRequestContext } from '@playwright/test';

interface LinkResult {
  url: string;
  status: number;
  foundOn: string;
}

async function checkAllLinks(
  page: Page,
  request: APIRequestContext,
  startUrl: string
): Promise<LinkResult[]> {
  const visited = new Set<string>();
  const results: LinkResult[] = [];
  const toVisit = [startUrl];
  const baseUrl = new URL(startUrl).origin;

  while (toVisit.length > 0) {
    const currentUrl = toVisit.pop()!;
    if (visited.has(currentUrl)) continue;
    visited.add(currentUrl);

    try {
      await page.goto(currentUrl);
      const links = await page.locator('a[href]').all();

      for (const link of links) {
        const href = await link.getAttribute('href');
        if (!href || href.startsWith('#') || href.startsWith('mailto:') || href.startsWith('tel:')) {
          continue;
        }

        const fullUrl = href.startsWith('http') ? href : new URL(href, currentUrl).href;

        // Check link
        const response = await request.get(fullUrl, {
          timeout: 10000,
          ignoreHTTPSErrors: true,
        });

        results.push({
          url: fullUrl,
          status: response.status(),
          foundOn: currentUrl,
        });

        // Add internal links to queue
        if (fullUrl.startsWith(baseUrl) && !visited.has(fullUrl)) {
          toVisit.push(fullUrl);
        }
      }
    } catch (error) {
      results.push({
        url: currentUrl,
        status: 0,
        foundOn: 'navigation',
      });
    }
  }

  return results;
}

test('no dead links on entire site', async ({ page, request, baseURL }) => {
  const results = await checkAllLinks(page, request, baseURL!);
  const deadLinks = results.filter(r => r.status >= 400 || r.status === 0);

  if (deadLinks.length > 0) {
    console.error('Dead links found:');
    deadLinks.forEach(link => {
      console.error(`  ${link.url} (${link.status}) - found on ${link.foundOn}`);
    });
  }

  expect(deadLinks, `Found ${deadLinks.length} dead links`).toHaveLength(0);
});

Image Link Validation

// e2e/tests/images.spec.ts
import { test, expect } from '@playwright/test';

test('no broken images on homepage', async ({ page, request }) => {
  await page.goto('/');

  const images = await page.locator('img[src]').all();

  for (const img of images) {
    const src = await img.getAttribute('src');
    if (!src) continue;

    const url = src.startsWith('http') ? src : new URL(src, page.url()).href;

    // Skip data URLs
    if (url.startsWith('data:')) continue;

    const response = await request.get(url);
    expect(
      response.ok(),
      `Broken image: ${src}`
    ).toBeTruthy();

    // Verify it's actually an image
    const contentType = response.headers()['content-type'];
    expect(
      contentType?.startsWith('image/'),
      `${src} is not an image (${contentType})`
    ).toBeTruthy();
  }
});

CI Integration for Link Checking

# .github/workflows/link-check.yml
name: Link Check

on:
  schedule:
    - cron: '0 6 * * 1'  # Weekly on Monday
  push:
    branches: [main]

jobs:
  link-check:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - uses: actions/setup-node@v4
        with:
          node-version: 20
      - run: npm ci
      - run: npx playwright install chromium
      - run: npx playwright test e2e/tests/links.spec.ts --project=chromium
        env:
          BASE_URL: ${{ secrets.PRODUCTION_URL }}

Anti-Patterns

Hardcoded waits - Use auto-waiting assertions instead

CSS/XPath selectors - Use role/text/testid locators

Testing third-party sites - Mock external dependencies

Shared state between tests - Each test must be isolated

Missing awaits - Use ESLint rule no-floating-promises

Flaky time-based tests - Mock dates/times

Testing implementation details - Test user-visible behavior

Huge test files - Split by feature/page

Quick Reference

# Install
npm init playwright@latest

# Run tests
npx playwright test
npx playwright test --headed
npx playwright test --project=chromium
npx playwright test --grep @smoke

# Debug
npx playwright test --debug
npx playwright show-report
npx playwright show-trace trace.zip

# Generate tests
npx playwright codegen localhost:3000

Package.json Scripts

{
  "scripts": {
    "test:e2e": "playwright test",
    "test:e2e:headed": "playwright test --headed",
    "test:e2e:debug": "playwright test --debug",
    "test:e2e:report": "playwright show-report",
    "test:e2e:codegen": "playwright codegen"
  }
}