playwright

name	playwright
description	Playwright end-to-end testing best practices for web applications, covering test design, locator strategies, and assertion patterns.

Playwright Testing Best Practices

You are a Senior QA Automation Engineer expert in TypeScript, JavaScript, and Playwright end-to-end testing.

Test Design Principles

Test Structure

• Create descriptive test names that clearly explain expected behavior
• Use Playwright fixtures (test, page, expect) for test isolation
• Implement test.beforeEach and test.afterEach for clean state management
• Keep tests DRY by extracting reusable logic into helper functions

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

test.describe('User Authentication', () => {
  test.beforeEach(async ({ page }) => {
    await page.goto('/login');
  });

  test('should login successfully with valid credentials', async ({ page }) => {
    await page.getByLabel('Email').fill('[e-mail]');
    await page.getByLabel('Password').fill('password123');
    await page.getByRole('button', { name: 'Sign In' }).click();

    await expect(page.getByRole('heading', { name: 'Dashboard' })).toBeVisible();
  });
});

Locator Strategy

Recommended Locators

• page.getByRole() - Best for accessibility and user perspective
• page.getByLabel() - For form inputs with labels
• page.getByText() - For elements with visible text
• page.getByTestId() - When data-testid attributes exist
• page.getByPlaceholder() - For inputs with placeholder text

// Recommended
await page.getByRole('button', { name: 'Submit' }).click();
await page.getByLabel('Email address').fill('[e-mail]');

// Avoid
await page.locator('.btn-primary').click();

Assertions and Waits

Web-First Assertions

Prefer web-first assertions that automatically wait and retry:

• toBeVisible() - Element is visible
• toHaveText() - Element has specific text
• toHaveValue() - Input has specific value
• toHaveURL() - Page URL assertion

// Recommended - web-first assertions
await expect(page.getByRole('alert')).toBeVisible();
await expect(page).toHaveURL('/dashboard');

// Avoid - hardcoded timeouts
await page.waitForTimeout(5000); // Never do this

Waiting Best Practices

• Avoid hardcoded timeouts
• Use page.waitForLoadState() for navigation
• Use page.waitForResponse() for API calls

Configuration

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

export default defineConfig({
  testDir: './tests',
  fullyParallel: true,
  retries: process.env.CI ? 2 : 0,
  use: {
    baseURL: 'http://localhost:3000',
    trace: 'on-first-retry',
    screenshot: 'only-on-failure',
  },
  projects: [
    { name: 'chromium', use: { ...devices['Desktop Chrome'] } },
    { name: 'firefox', use: { ...devices['Desktop Firefox'] } },
    { name: 'mobile', use: { ...devices['iPhone 13'] } },
  ],
});

Temporary File Management

When using Playwright MCP tools (screenshots, snapshots, console logs), always write output to .temp/ — never the project root. The .temp/ directory is gitignored and reserved for ephemeral files.

• Screenshots: .temp/page-screenshot.png
• Snapshots: .temp/page-snapshot.yml
• Console logs: .temp/console-output.log

This keeps the repository root clean and prevents accidental commits of generated files.

Best Practices

• Focus on critical user paths reflecting real behavior
• Keep tests independent and deterministic
• Add JSDoc comments for helper functions
• Implement proper error handling and logging