Add Vitest tests for the languages, router, footer and pages, and a lint:check script

tests/locale-utils.test.js

@@ -0,0 +1,67 @@
+/**
+ * The helpers that build and switch the /<language>/... paths. Every link on
+ * the site goes through these, so a slip here breaks navigation everywhere.
+ */
+
+import { getCurrentLocale, getLocalizedPath, switchLocale } from '@/utils/locale'
+
+afterEach(() => {
+  delete window.i18n
+})
+
+describe('getLocalizedPath', () => {
+  test('puts the language first, with or without a leading slash on the page', () => {
+    expect(getLocalizedPath('servers', 'de')).toBe('/de/servers')
+    expect(getLocalizedPath('/servers', 'de')).toBe('/de/servers')
+  })
+
+  test('never doubles a slash', () => {
+    expect(getLocalizedPath('//servers', 'fr')).toBe('/fr/servers')
+    expect(getLocalizedPath('', 'fr')).toBe('/fr/')
+  })
+
+  test('uses the saved language when none is given, and English if nothing is saved', () => {
+    expect(getLocalizedPath('about')).toBe('/en/about')
+    localStorage.setItem('lang', 'it')
+    expect(getLocalizedPath('about')).toBe('/it/about')
+  })
+
+  test('the language the app is showing wins over the saved one', () => {
+    localStorage.setItem('lang', 'it')
+    window.i18n = { global: { locale: { value: 'ru' } } }
+    expect(getLocalizedPath('about')).toBe('/ru/about')
+  })
+})
+
+describe('getCurrentLocale', () => {
+  test('reads a plain string locale as well as a ref', () => {
+    window.i18n = { global: { locale: 'es' } }
+    expect(getCurrentLocale()).toBe('es')
+    window.i18n = { global: { locale: { value: 'zh' } } }
+    expect(getCurrentLocale()).toBe('zh')
+  })
+})
+
+describe('switchLocale', () => {
+  test('swaps the language and keeps the page', () => {
+    expect(switchLocale('de', '/en/servers')).toBe('/de/servers')
+    expect(switchLocale('fr', '/ru/about')).toBe('/fr/about')
+  })
+
+  test('keeps deeper paths', () => {
+    expect(switchLocale('de', '/en/docs/getting-started')).toBe('/de/docs/getting-started')
+  })
+
+  test('the home page of one language is the home page of the next', () => {
+    expect(switchLocale('es', '/en')).toBe('/es')
+    expect(switchLocale('es', '/en/')).toBe('/es')
+  })
+
+  test('drops the old query string rather than carrying it across', () => {
+    expect(switchLocale('de', '/en/servers?search=drift')).toBe('/de/servers')
+  })
+
+  test('adds a language to a path that has none', () => {
+    expect(switchLocale('de', '/servers')).toBe('/de/servers')
+  })
+})