feat(SPA): i18n internationzalization, english and french

web/src/i18n/i18n.spec.ts

@@ -0,0 +1,54 @@
+import { afterEach, describe, expect, it, vi } from 'vitest'
+import { initializeLocale, locale, setLocale, t, formatNumber } from './index'
+
+afterEach(() => {
+	vi.restoreAllMocks()
+	localStorage.clear()
+	initializeLocale()
+})
+
+describe('Resolve the language before rendering', () => {
+	it('keeps English default with a French browser', () => {
+		vi.spyOn(navigator, 'language', 'get').mockReturnValue('fr-FR')
+		localStorage.clear()
+		initializeLocale()
+		expect([locale.value, document.documentElement.lang]).toEqual(['en', 'en'])
+	})
+	it.each([null, 'en', 'fr', 'unsupported'])(
+		'resolves stored %s independently of browser language',
+		(stored) => {
+			if (stored) localStorage.setItem('renewcms-language', stored)
+			initializeLocale()
+			expect([locale.value, document.documentElement.lang]).toEqual(
+				stored === 'fr' ? ['fr', 'fr'] : ['en', 'en'],
+			)
+		},
+	)
+	it('defaults to English when preference storage is unreadable', () => {
+		setLocale('fr')
+		vi.spyOn(Storage.prototype, 'getItem').mockImplementation(() => {
+			throw new Error('denied')
+		})
+		initializeLocale()
+		expect([locale.value, document.documentElement.lang]).toEqual(['en', 'en'])
+	})
+})
+
+describe('Remember language on this browser', () => {
+	it('restores the selected French language on initialization', () => {
+		setLocale('fr')
+		initializeLocale()
+		expect(locale.value).toBe('fr')
+	})
+	it('switches when storage cannot be written', () => {
+		vi.spyOn(Storage.prototype, 'setItem').mockImplementation(() => {
+			throw new Error('denied')
+		})
+		setLocale('fr')
+		expect([t('Log in'), document.documentElement.lang]).toEqual(['Se connecter', 'fr'])
+	})
+	it('formats numbers according to the selected locale', () => {
+		setLocale('fr')
+		expect(formatNumber(1234.5)).toBe(new Intl.NumberFormat('fr').format(1234.5))
+	})
+})