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

```typescript
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('user@example.com');
    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

```typescript
// Recommended
await page.getByRole('button', { name: 'Submit' }).click();
await page.getByLabel('Email address').fill('test@example.com');

// 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

```typescript
// 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

```typescript
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'] } },
  ],
});
```

## 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