/localization-testing

name: localization-testing
description: "Internationalization (i18n) and localization (l10n) testing for global products including translations, locale formats, RTL languages, and cultural appropriateness. Use when launching in new markets or building multi-language products."
category: specialized-testing
priority: medium
tokenEstimate: 800
agents: [qe-test-generator, qe-test-executor, qe-visual-tester]
implementation_status: optimized
optimization_version: 1.0
last_optimized: 2025-12-02
dependencies: []
quick_reference_card: true
tags: [localization, i18n, l10n, translation, rtl, unicode, locale]
trust_tier: 3
validation:
  schema_path: schemas/output.json
  validator_path: scripts/validate-config.json
  eval_path: evals/localization-testing.yaml

Localization & Internationalization Testing

Browser engine

Browser-driven locale checks (RTL layout diffs, language-switching flows, locale-specific screenshots) should go through the **qe-browser** fleet skill. Example:

vibium go "$BASE_URL?lang=ar"  # Arabic, RTL
vibium wait load
node .claude/skills/qe-browser/scripts/visual-diff.js --name homepage-ar-rtl
vibium go "$BASE_URL?lang=ja"  # Japanese, CJK text expansion
node .claude/skills/qe-browser/scripts/visual-diff.js --name homepage-ja

See `.claude/skills/qe-browser/SKILL.md` for the full reference.

<default_to_action> When testing multi-language/region support: 1. VERIFY translation coverage (all strings translated) 2. TEST locale-specific formats (date, time, currency, numbers) 3. VALIDATE RTL layout (Arabic, Hebrew) 4. CHECK character encoding (UTF-8, unicode) 5. CONFIRM cultural appropriateness (icons, colors, content)

**Quick i18n Checklist:**

• All user-facing strings externalized
• No hardcoded text in code
• Date/time/currency formatted per locale
• RTL languages flip layout correctly
• Unicode characters display properly

**Critical Success Factors:**

• Don't hardcode strings - externalize everything
• Test with real speakers, not just translation files
• RTL requires mirrored UI layout

</default_to_action>

Quick Reference Card

When to Use

• Launching in new markets
• Adding language support
• Before international releases
• After UI changes

---

Translation Coverage Testing

test('all strings are translated', () => {
  const enKeys = Object.keys(translations.en);
  const frKeys = Object.keys(translations.fr);
  const esKeys = Object.keys(translations.es);

  // All locales have same keys
  expect(frKeys).toEqual(enKeys);
  expect(esKeys).toEqual(enKeys);
});

test('no missing translation placeholders', async ({ page }) => {
  await page.goto('/?lang=fr');
  const text = await page.textContent('body');

  // Should not see placeholder keys
  expect(text).not.toContain('translation.missing');
  expect(text).not.toMatch(/\{\{.*\}\}/); // {{key}} format
});

---

Date/Time/Currency Formats

test('date formats by locale', () => {
  const date = new Date('2025-10-24');

  expect(formatDate(date, 'en-US')).toBe('10/24/2025');
  expect(formatDate(date, 'en-GB')).toBe('24/10/2025');
  expect(formatDate(date, 'ja-JP')).toBe('2025/10/24');
});

test('currency formats by locale', () => {
  const amount = 1234.56;

  expect(formatCurrency(amount, 'en-US', 'USD')).toBe('$1,234.56');
  expect(formatCurrency(amount, 'de-DE', 'EUR')).toBe('1.234,56 €');
  expect(formatCurrency(amount, 'ja-JP', 'JPY')).toBe('¥1,235');
});

---

RTL (Right-to-Left) Testing

test('layout flips for RTL languages', async ({ page }) => {
  await page.goto('/?lang=ar'); // Arabic

  const dir = await page.locator('html').getAttribute('dir');
  expect(dir).toBe('rtl');

  // Navigation should be on right
  const nav = await page.locator('nav');
  const styles = await nav.evaluate(el =>
    window.getComputedStyle(el)
  );
  expect(styles.direction).toBe('rtl');
});

test('icons/images appropriate for RTL', async ({ page }) => {
  await page.goto('/?lang=he'); // Hebrew

  // Back arrow should point right in RTL
  const backIcon = await page.locator('.back-icon');
  expect(await backIcon.getAttribute('class')).toContain('rtl-flipped');
});

---

Unicode Character Support

test('supports unicode characters', async ({ page }) => {
  // Japanese
  await page.fill('#name', '山田太郎');
  await page.click('#submit');

  const saved = await db.users.findOne({ /* ... */ });
  expect(saved.name).toBe('山田太郎');

  // Arabic
  await page.fill('#name', 'محمد');
  // Emoji
  await page.fill('#bio', '👋🌍');

  expect(saved.bio).toBe('👋🌍');
});

---

Agent-Driven Localization Testing

// Comprehensive localization validation
await Task("Localization Testing", {
  url: 'https://example.com',
  locales: ['en-US', 'fr-FR', 'de-DE', 'ja-JP', 'ar-SA'],
  checks: ['translations', 'formats', 'rtl', 'unicode'],
  detectHardcodedStrings: true
}, "qe-test-generator");

// Returns:
// {
//   locales: 5,
//   missingTranslations: 3,
//   formatIssues: 1,
//   rtlIssues: 0,
//   hardcodedStrings: ['button.submit', 'header.title']
// }

---

Agent Coordination Hints

Memory Namespace

aqe/localization-testing/
├── translations/*       - Translation coverage
├── formats/*            - Locale-specific formats
├── rtl-validation/*     - RTL layout checks
└── unicode/*            - Character encoding tests

Fleet Coordination

const l10nFleet = await FleetManager.coordinate({
  strategy: 'localization-testing',
  agents: [
    'qe-test-generator',   // Generate l10n tests
    'qe-test-executor',    // Execute across locales
    'qe-visual-tester'     // RTL visual validation
  ],
  topology: 'parallel'
});

---

Related Skills

• [accessibility-testing](../accessibility-testing/) - Language accessibility
• [compatibility-testing](../compatibility-testing/) - Cross-platform i18n
• [visual-testing-advanced](../visual-testing-advanced/) - RTL visual regression

---

Remember