Compatibility Testing

<default_to_action> When validating cross-browser/platform compatibility:

• DEFINE browser matrix (cover 95%+ of users)

• TEST responsive breakpoints (mobile, tablet, desktop)

• RUN in parallel across browsers/devices

• USE cloud services for device coverage (BrowserStack, Sauce Labs)

• COMPARE visual screenshots across platforms

Quick Compatibility Checklist:

• Chrome, Firefox, Safari, Edge (latest + N-1)

• Mobile Safari (iOS), Mobile Chrome (Android)

• Screen sizes: 320px, 768px, 1920px

• Test on actual target devices for critical flows

Critical Success Factors:

• Users access from 100+ browser/device combinations

• Test where users are, not where you develop

• Cloud testing reduces 10 hours to 15 minutes </default_to_action>

Quick Reference Card

When to Use

• Before release

• After CSS/layout changes

• Launching in new markets

• Responsive design validation

Browser Matrix

Browser Versions Priority

Chrome Latest, N-1 High

Firefox Latest, N-1 High

Safari Latest, N-1 High

Edge Latest Medium

Mobile Safari iOS latest High

Mobile Chrome Android latest High

Screen Breakpoints

Category Width Range

Mobile 320px - 480px

Tablet 481px - 768px

Desktop 769px - 1920px+

Responsive Design Testing

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

const devices = [ { name: 'iPhone 12', width: 390, height: 844 }, { name: 'iPad', width: 768, height: 1024 }, { name: 'Desktop', width: 1920, height: 1080 } ];

for (const device of devices) { test(layout on ${device.name}, async ({ page }) => { await page.setViewportSize({ width: device.width, height: device.height });

await page.goto('https://example.com');

const nav = await page.locator('nav');
if (device.width < 768) {
  // Mobile: hamburger menu
  expect(await nav.locator('.hamburger')).toBeVisible();
} else {
  // Desktop: full menu
  expect(await nav.locator('.menu-items')).toBeVisible();
}

}); }

Cross-Browser with Playwright

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

export default defineConfig({ projects: [ { name: 'chromium', use: { ...devices['Desktop Chrome'] } }, { name: 'firefox', use: { ...devices['Desktop Firefox'] } }, { name: 'webkit', use: { ...devices['Desktop Safari'] } }, { name: 'mobile-chrome', use: { ...devices['Pixel 5'] } }, { name: 'mobile-safari', use: { ...devices['iPhone 12'] } } ] });

// Run: npx playwright test --project=chromium --project=firefox

Cloud Testing Integration

// BrowserStack configuration const capabilities = { 'browserName': 'Chrome', 'browser_version': '118.0', 'os': 'Windows', 'os_version': '11', 'browserstack.user': process.env.BROWSERSTACK_USER, 'browserstack.key': process.env.BROWSERSTACK_KEY };

// Parallel execution across devices const deviceMatrix = [ { os: 'Windows', browser: 'Chrome' }, { os: 'OS X', browser: 'Safari' }, { os: 'Android', device: 'Samsung Galaxy S24' }, { os: 'iOS', device: 'iPhone 15' } ];

Agent-Driven Compatibility Testing

// Cross-platform visual comparison await Task("Compatibility Testing", { url: 'https://example.com', browsers: ['chrome', 'firefox', 'safari', 'edge'], devices: ['desktop', 'tablet', 'mobile'], platform: 'browserstack', parallel: true }, "qe-visual-tester");

// Returns: // { // combinations: 12, // 4 browsers × 3 devices // passed: 11, // differences: [{ browser: 'safari', device: 'mobile', diff: 0.02 }] // }

Agent Coordination Hints

Memory Namespace

aqe/compatibility-testing/ ├── browser-matrix/* - Browser/version configurations ├── device-matrix/* - Device configurations ├── visual-diffs/* - Cross-browser visual differences └── reports/* - Compatibility reports

Fleet Coordination

const compatFleet = await FleetManager.coordinate({ strategy: 'compatibility-testing', agents: [ 'qe-visual-tester', // Visual comparison 'qe-test-executor', // Cross-browser execution 'qe-performance-tester' // Performance by platform ], topology: 'parallel' });

Related Skills

• mobile-testing - Mobile-specific testing

• visual-testing-advanced - Visual regression

• accessibility-testing - Cross-platform a11y

Remember

Test where users are, not where you develop. Developers use latest Chrome on high-end machines. Users access from older browsers, low-end devices, and slow networks.

Cover 95%+ of your user base. Use analytics to identify actual browser/device usage. Don't waste time on browsers nobody uses.

With Agents: Agents orchestrate parallel cross-browser testing across cloud platforms, reducing 10 hours of manual testing to 15 minutes. qe-visual-tester catches visual inconsistencies across platforms automatically.