feat: add multilingual interface support

test/deployment.test.js

@@ -0,0 +1,24 @@
+const test = require("node:test");
+const assert = require("node:assert/strict");
+const fs = require("node:fs");
+const path = require("node:path");
+
+const root = path.resolve(__dirname, "..");
+
+test("the Docker image includes every application script referenced by the page", () => {
+  const html = fs.readFileSync(path.join(root, "index.html"), "utf8");
+  const dockerfile = fs.readFileSync(path.join(root, "Dockerfile"), "utf8");
+  const applicationScripts = [...html.matchAll(/<script src="\.\/([^"]+\.js)"/g)]
+    .map((match) => match[1])
+    .filter((scriptPath) => !scriptPath.startsWith("vendor/"));
+
+  assert.ok(applicationScripts.length > 0);
+  applicationScripts.forEach((scriptPath) => {
+    assert.ok(fs.existsSync(path.join(root, scriptPath)), `${scriptPath} must exist`);
+    assert.match(
+      dockerfile,
+      new RegExp(`^COPY ${scriptPath.replace(/[.*+?^${}()|[\]\\]/g, "\\$&")} \\.\\/$`, "m"),
+      `${scriptPath} must be copied by the Dockerfile`,
+    );
+  });
+});

test/i18n.test.js

@@ -0,0 +1,85 @@
+const test = require("node:test");
+const assert = require("node:assert/strict");
+
+const {
+  DEFAULT_LANGUAGE,
+  TRANSLATIONS,
+  createI18n,
+  detectLanguage,
+  normalizeLanguage,
+} = require("../i18n.js");
+
+function createStorage(initialValue) {
+  let value = initialValue;
+  return {
+    getItem() {
+      return value;
+    },
+    setItem(key, nextValue) {
+      value = nextValue;
+    },
+    removeItem() {
+      value = undefined;
+    },
+  };
+}
+
+test("normalizes exact and base language tags", () => {
+  assert.equal(normalizeLanguage("pt-PT"), "pt-PT");
+  assert.equal(normalizeLanguage("pt-BR"), "pt-PT");
+  assert.equal(normalizeLanguage("en-US"), "en");
+  assert.equal(normalizeLanguage("fr"), null);
+});
+
+test("prefers a stored language over browser preferences", () => {
+  const storage = createStorage("en");
+  assert.equal(detectLanguage({ storage, languages: ["pt-PT"] }), "en");
+});
+
+test("uses the first supported browser language and otherwise falls back", () => {
+  assert.equal(detectLanguage({ storage: createStorage(), languages: ["fr", "pt-BR"] }), "pt-PT");
+  assert.equal(detectLanguage({ storage: createStorage(), languages: ["es-MX"] }), "es");
+  assert.equal(detectLanguage({ storage: createStorage(), languages: ["fr"] }), DEFAULT_LANGUAGE);
+});
+
+test("persists language changes and interpolates translated values", () => {
+  const storage = createStorage();
+  const i18n = createI18n({ storage, languages: ["en"] });
+
+  assert.equal(i18n.setLanguage("pt"), "pt-PT");
+  assert.equal(storage.getItem(), "pt-PT");
+  assert.equal(
+    i18n.t("noParcelFound", { parcelNumber: "57" }),
+    "Não foi encontrada a parcela com o número “57”.",
+  );
+});
+
+test("browser-default mode removes the preference and follows the browser language", () => {
+  const storage = createStorage("en");
+  const i18n = createI18n({ storage, languages: ["pt-PT"] });
+
+  assert.equal(i18n.setLanguage(null), "pt-PT");
+  assert.equal(i18n.preference, null);
+  assert.equal(storage.getItem(), undefined);
+});
+
+test("uses English for missing translations and the key for unknown messages", () => {
+  const storage = createStorage("pt-PT");
+  const originalTranslation = TRANSLATIONS["pt-PT"].zoomIn;
+  delete TRANSLATIONS["pt-PT"].zoomIn;
+
+  try {
+    const i18n = createI18n({ storage, languages: [] });
+    assert.equal(i18n.t("zoomIn"), TRANSLATIONS.en.zoomIn);
+    assert.equal(i18n.t("notARealMessage"), "notARealMessage");
+  } finally {
+    TRANSLATIONS["pt-PT"].zoomIn = originalTranslation;
+  }
+});
+
+test("all shipped languages contain the default translation keys", () => {
+  const defaultKeys = Object.keys(TRANSLATIONS[DEFAULT_LANGUAGE]).sort();
+  Object.entries(TRANSLATIONS).forEach(([language, translations]) => {
+    assert.deepEqual(Object.keys(translations).sort(), defaultKeys, language);
+  });
+});