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

tests/helpers.js

@@ -0,0 +1,90 @@
+import fs from 'node:fs'
+import path from 'node:path'
+import { fileURLToPath } from 'node:url'
+import { flushPromises, mount } from '@vue/test-utils'
+import { setupI18n } from '@/i18n'
+import en from '@/locales/en.json'
+import router from '@/routes'
+import App from '@/App.vue'
+
+export const root = path.resolve(path.dirname(fileURLToPath(import.meta.url)), '..')
+export const publicFile = (name) => fs.readFileSync(path.join(root, 'public', name), 'utf8')
+
+// The same i18n the app builds in main.js, with English loaded. The router's
+// guard reads window.i18n to switch language, so it is set here too.
+export function installI18n(locale = 'en') {
+  const i18n = setupI18n({ legacy: false, locale, fallbackLocale: 'en', messages: { en } })
+  window.i18n = i18n
+  return i18n
+}
+
+const reply = (body, ok = true, status = ok ? 200 : 503) => ({
+  ok,
+  status,
+  json: async () => (typeof body === 'string' ? JSON.parse(body) : body),
+  text: async () => (typeof body === 'string' ? body : JSON.stringify(body)),
+})
+
+/**
+ * Stands in for fetch. Local files come from the repo's public folder; the
+ * backend feeds can be given as data, or left to answer 503 ("backend down").
+ * Nothing reaches the network, and a URL nobody planned for fails the test.
+ */
+export function stubFetch({ servers, metrics } = {}) {
+  const calls = []
+  const stub = async (url) => {
+    const address = String(url)
+    calls.push(address)
+    if (
+      address.startsWith('/docs/') ||
+      address === '/partners.json' ||
+      address === '/servers.json'
+    ) {
+      return reply(publicFile(address.slice(1)))
+    }
+    if (address === 'https://backend.beammp.com/servers-info')
+      return servers ? reply(servers) : reply('', false)
+    if (address === 'https://api.beammp.com/metrics')
+      return metrics ? reply(metrics) : reply('', false)
+    // The statistics page's release and stats feeds: down unless a test says otherwise.
+    if (
+      /^https:\/\/(api|backend)\.beammp\.com\//.test(address) ||
+      address.startsWith('https://api.github.com/')
+    )
+      return reply('', false)
+    throw new Error(`Unplanned fetch to ${address}`)
+  }
+  stub.calls = calls
+  vi.stubGlobal('fetch', stub)
+  return stub
+}
+
+/**
+ * Runs `action` (a navigation) and fails it if the router's language guard
+ * keeps redirecting. A runaway redirect would otherwise freeze the test run
+ * the way it freezes the page. The guard reads the saved language on every
+ * redirect, which is what is counted.
+ */
+export async function withRedirectLimit(action, limit = 5) {
+  const real = localStorage.getItem.bind(localStorage)
+  let passes = 0
+  localStorage.getItem = (key) => {
+    if (key === 'lang' && ++passes > limit) throw new Error('still redirecting')
+    return real(key)
+  }
+  try {
+    return await action()
+  } finally {
+    localStorage.getItem = real
+  }
+}
+
+/** Opens a page of the real app (router, layout, nav and footer) and lets it finish loading. */
+export async function openPage(pathname) {
+  const i18n = installI18n('en')
+  await withRedirectLimit(() => router.push(pathname))
+  await router.isReady()
+  const wrapper = mount(App, { attachTo: document.body, global: { plugins: [i18n, router] } })
+  await flushPromises()
+  return wrapper
+}