openidea/src/platform/i18n.test.ts

import { afterEach, describe, expect, it } from "vitest";
import {
  _resetI18nForTests,
  formatMessage,
  isValidMessage,
  keysWithPrefix,
  registerMessages,
  resolveLocale,
  setLocale,
  t,
  tx,
  txTemplate,
  useI18n,
} from "./i18n";
import en from "./locales/en.json";
import zh from "./locales/zh.json";
import zhText from "./locales/text/zh.json";

afterEach(() => _resetI18nForTests());

describe("formatMessage", () => {
  it("substitutes parameters and leaves unknown ones", () => {
    expect(formatMessage("Open {name}", { name: "openidea" })).toBe("Open openidea");
    expect(formatMessage("Open {name} in {where}", { name: "openidea" })).toBe("Open openidea in {where}");
    expect(formatMessage("plain text")).toBe("plain text");
  });

  it("formats numbers per locale", () => {
    expect(formatMessage("{n} files", { n: 12345 }, "en")).toBe("12,345 files");
    expect(formatMessage("{n, number}", { n: 1234.5 }, "en")).toBe("1,234.5");
  });

  it("selects plural categories, exact matches first", () => {
    const m = "{count, plural, =0 {No files} one {# file} other {# files}}";
    expect(formatMessage(m, { count: 0 })).toBe("No files");
    expect(formatMessage(m, { count: 1 })).toBe("1 file");
    expect(formatMessage(m, { count: 2 })).toBe("2 files");
    expect(formatMessage(m, { count: 1000 })).toBe("1,000 files");
  });

  it("uses CLDR rules of the locale (Chinese has only `other`)", () => {
    const m = "{count, plural, one {# one} other {# other}}";
    expect(formatMessage(m, { count: 1 }, "zh")).toBe("1 other");
    expect(formatMessage(m, { count: 1 }, "en")).toBe("1 one");
  });

  it("supports select and nesting", () => {
    const m = "{os, select, macos {Finder} windows {Explorer} other {Files}}";
    expect(formatMessage(m, { os: "macos" })).toBe("Finder");
    expect(formatMessage(m, { os: "linux" })).toBe("Files");
    const nested = "{count, plural, one {{who} has # file} other {{who} has # files}}";
    expect(formatMessage(nested, { count: 3, who: "Ann" })).toBe("Ann has 3 files");
    const deep = "{os, select, macos {{count, plural, one {# window} other {# windows}}} other {#}}";
    expect(formatMessage(deep, { os: "macos", count: 2 })).toBe("2 windows");
  });

  it("falls back to `other` when the parameter is missing", () => {
    expect(formatMessage("{n, plural, one {one} other {many}}")).toBe("many");
  });

  it("returns malformed messages unformatted", () => {
    expect(formatMessage("{n, plural, one {x}", { n: 1 })).toBe("{n, plural, one {x}");
    expect(formatMessage("{n, weird, a {b}}", { n: 1 })).toBe("{n, weird, a {b}}");
    expect(isValidMessage("{n, plural, one {x}")).toBe(false);
    expect(isValidMessage("{n, plural, one {x} other {y}}")).toBe(true);
  });
});

describe("t / locales", () => {
  it("resolves locale tags", () => {
    expect(resolveLocale("zh-CN")).toBe("zh");
    expect(resolveLocale("zh_Hans")).toBe("zh");
    expect(resolveLocale("EN-us")).toBe("en");
    expect(resolveLocale("fr")).toBe("en");
    expect(resolveLocale(undefined)).toBe(resolveLocale(navigator.language));
  });

  it("translates with English fallback, then the key itself", async () => {
    expect(t("common.cancel")).toBe("Cancel");
    await setLocale("zh");
    expect(useI18n.getState().locale).toBe("zh");
    expect(t("common.cancel")).toBe("取消");
    registerMessages("en", { "test.onlyEnglish": "Only English" });
    expect(t("test.onlyEnglish")).toBe("Only English");
    expect(t("test.missing.key")).toBe("test.missing.key");
  });

  it("applies params and plurals in the active locale", async () => {
    expect(t("app.unsaved.body", { count: 1, project: "openidea" })).toBe(
      "1 file has unsaved changes in openidea. Save before closing?",
    );
    await setLocale("zh-CN");
    expect(t("app.keymap.count", { count: 1 })).toBe("1 个快捷键");
  });

  it("falls back to English for unsupported locales", async () => {
    await setLocale("de");
    expect(useI18n.getState().locale).toBe("en");
  });

  it("registerMessages adds and removes feature strings", async () => {
    const off = registerMessages("zh", { "feature.hello": "你好" });
    registerMessages("en", { "feature.hello": "Hello" });
    expect(t("feature.hello")).toBe("Hello");
    await setLocale("zh");
    expect(t("feature.hello")).toBe("你好");
    off();
    expect(t("feature.hello")).toBe("Hello");
  });

  it("translates source text through the locale's text catalog", async () => {
    await setLocale("en");
    expect(tx("Sync with OS")).toBe("Sync with OS");
    await setLocale("zh");
    expect(tx("Sync with OS")).toBe("与操作系统同步");
    expect(tx("Some text nobody translated")).toBe("Some text nobody translated");
    expect(tx(undefined)).toBeUndefined();
  });

  it("matches source-text templates, translating the substituted text", async () => {
    expect(txTemplate("Push failed")).toBe("Push failed");
    await setLocale("zh");
    expect(txTemplate("ruff is not installed")).toBe("ruff 未安装");
    expect(txTemplate("Language server 'gopls' is not installed")).toBe("语言服务器 'gopls' 未安装");
    expect(txTemplate("Retry failed")).toBe(`${tx("Retry")}失败`);
    expect(txTemplate("Sync with OS")).toBe("与操作系统同步");
    expect(txTemplate("Something else entirely")).toBe("Something else entirely");
  });

  it("translates text built by the tx tag, again after the locale changes", async () => {
    await setLocale("en");
    const name = "orders";
    const built = tx`Run '${name}'`;
    expect(built).toBe("Run 'orders'");
    expect(tx`Unknown ${name} text`).toBe("Unknown orders text");
    await setLocale("zh");
    // Built before the catalog loaded: primitives passing it through `tx` translate it.
    expect(tx(built)).toBe("运行 'orders'");
    expect(txTemplate(built)).toBe("运行 'orders'");
    const zh = tx`Run '${name}'`;
    expect(zh).toBe("运行 'orders'");
    // Substituted text is translated when the catalog has it.
    expect(tx`Run '${"Retry"}'`).toBe(`运行 '${tx("Retry")}'`);
    // Values are inserted as they are, braces included.
    expect(tx`Drop ${"stash@{0}"}? This cannot be undone.`).toBe("是否丢弃 stash@{0}？此操作无法撤消。");
    await setLocale("en");
    expect(tx(zh)).toBe("Run 'orders'");
  });

  it("lists keys by prefix", () => {
    const keys = keysWithPrefix("menu.");
    expect(keys).toContain("menu.file.save");
    expect(keys.every((k) => k.startsWith("menu."))).toBe(true);
  });
});

describe("catalogs", () => {
  const catalogs: Record<string, Record<string, string>> = { en, zh };

  it("translate source text into non-empty, different text", () => {
    for (const [source, text] of Object.entries(zhText as Record<string, string>)) {
      expect(text.trim(), source).not.toBe("");
      expect(text, source).not.toBe(source);
    }
  });

  it("keep the placeholders of source-text templates", () => {
    const names = (m: string) => [...m.matchAll(/\{(\w+)\}/g)].map((x) => x[1]).sort();
    for (const [source, text] of Object.entries(zhText as Record<string, string>))
      expect(names(text), source).toEqual(names(source));
  });

  it("have the same keys", () => {
    expect(Object.keys(zh).sort()).toEqual(Object.keys(en).sort());
  });

  it("contain only well-formed messages", () => {
    for (const [locale, catalog] of Object.entries(catalogs))
      for (const [key, message] of Object.entries(catalog))
        expect(isValidMessage(message), `${locale}:${key}`).toBe(true);
  });

  it("use the same parameters across locales", () => {
    const params = (m: string) => [...m.matchAll(/\{\s*([a-z]\w*)\s*[,}]/g)].map((x) => x[1]).sort();
    for (const key of Object.keys(en))
      expect(params((zh as Record<string, string>)[key] ?? ""), key).toEqual(
        params((en as Record<string, string>)[key]!),
      );
  });
});