test(frontend): #343 Jest+RTL 인프라 + ARIA Tabs + remotePatterns

테스트 인프라:
- Jest 30 + jest-environment-jsdom + RTL + jest-dom matchers
- next/jest로 SWC/Next.js 자동 통합
- jest.config.ts (setupFilesAfterEnv) + jest.setup.ts
- npm scripts: test, test:watch
- 샘플 테스트 3개, 13/13 통과:
  - i18n/config: isLocale + detectBrowserLocale (5 케이스)
  - Stars 컴포넌트: 별점/aria/clamp/showNumber (5 케이스)
  - admin-utils: getAdminToken + authHeaders (4 케이스)

ARIA Tabs (MyReviewsList):
- role=tablist + tab + aria-selected + aria-controls + tabIndex
- panel에 role=tabpanel + aria-labelledby

next/image:
- next.config.ts remotePatterns: lh3.googleusercontent.com / i.ytimg.com / yt3.ggpht.com
- ReviewSection의 user_avatar_url에 명시적 eslint-disable + 사유

후속(별도): 전체 컴포넌트 테스트 점진 추가, 백엔드 JUnit 인프라, E2E (Playwright), CI 통합

설계서: docs/design/343-frontend-test-infra/README.md

Refs: #343

frontend/__tests__/Stars.test.tsx

@@ -0,0 +1,36 @@
+/**
+ * #343 — Stars 컴포넌트 렌더 테스트.
+ */
+import { render, screen } from "@testing-library/react";
+import Stars from "@/components/Stars";
+
+describe("Stars", () => {
+  it("renders 5 star slots", () => {
+    const { container } = render(<Stars rating={3} />);
+    // 빈 별 5개 (text-gray-300 클래스 갖는 span)
+    const emptyStars = container.querySelectorAll("span.text-gray-300");
+    expect(emptyStars.length).toBe(5);
+  });
+
+  it("shows aria-label with rating", () => {
+    render(<Stars rating={4.5} />);
+    expect(screen.getByLabelText("4.5점")).toBeInTheDocument();
+  });
+
+  it("clamps rating to 0~5", () => {
+    render(<Stars rating={-1} />);
+    expect(screen.getByLabelText("0점")).toBeInTheDocument();
+    render(<Stars rating={10} />);
+    expect(screen.getByLabelText("5점")).toBeInTheDocument();
+  });
+
+  it("shows number when showNumber + rating > 0", () => {
+    const { container } = render(<Stars rating={3.5} showNumber />);
+    expect(container.textContent).toContain("3.5");
+  });
+
+  it("does not show number when rating is 0 even with showNumber", () => {
+    const { container } = render(<Stars rating={0} showNumber />);
+    expect(container.textContent).not.toContain("0");
+  });
+});

frontend/__tests__/admin-utils.test.ts

@@ -0,0 +1,28 @@
+/**
+ * #343 — admin-utils 순수 함수 단위 테스트.
+ */
+import { getAdminToken, authHeaders } from "@/lib/admin-utils";
+
+describe("admin-utils", () => {
+  beforeEach(() => {
+    localStorage.clear();
+  });
+
+  it("getAdminToken returns null when not set", () => {
+    expect(getAdminToken()).toBeNull();
+  });
+
+  it("getAdminToken returns stored token", () => {
+    localStorage.setItem("tasteby_token", "abc123");
+    expect(getAdminToken()).toBe("abc123");
+  });
+
+  it("authHeaders is empty when no token", () => {
+    expect(authHeaders()).toEqual({});
+  });
+
+  it("authHeaders includes Bearer when token set", () => {
+    localStorage.setItem("tasteby_token", "xyz");
+    expect(authHeaders()).toEqual({ Authorization: "Bearer xyz" });
+  });
+});

frontend/__tests__/i18n-config.test.ts

@@ -0,0 +1,42 @@
+/**
+ * #343 — i18n/config 순수 함수 단위 테스트.
+ */
+import { isLocale, detectBrowserLocale, DEFAULT_LOCALE } from "@/i18n/config";
+
+describe("i18n/config.isLocale", () => {
+  it("returns true for supported locales", () => {
+    expect(isLocale("ko")).toBe(true);
+    expect(isLocale("en")).toBe(true);
+    expect(isLocale("ja")).toBe(true);
+    expect(isLocale("es")).toBe(true);
+  });
+
+  it("returns false for unsupported / null / undefined", () => {
+    expect(isLocale("fr")).toBe(false);
+    expect(isLocale("zh")).toBe(false);
+    expect(isLocale(null)).toBe(false);
+    expect(isLocale(undefined)).toBe(false);
+    expect(isLocale("")).toBe(false);
+  });
+});
+
+describe("i18n/config.detectBrowserLocale", () => {
+  // jsdom의 navigator.language는 기본 'en-US'
+  it("returns supported locale from navigator.language", () => {
+    Object.defineProperty(navigator, "language", { value: "en-US", configurable: true });
+    expect(detectBrowserLocale()).toBe("en");
+    Object.defineProperty(navigator, "language", { value: "ko-KR", configurable: true });
+    expect(detectBrowserLocale()).toBe("ko");
+    Object.defineProperty(navigator, "language", { value: "ja", configurable: true });
+    expect(detectBrowserLocale()).toBe("ja");
+    Object.defineProperty(navigator, "language", { value: "es-MX", configurable: true });
+    expect(detectBrowserLocale()).toBe("es");
+  });
+
+  it("falls back to DEFAULT_LOCALE for unsupported", () => {
+    Object.defineProperty(navigator, "language", { value: "fr-FR", configurable: true });
+    expect(detectBrowserLocale()).toBe(DEFAULT_LOCALE);
+    Object.defineProperty(navigator, "language", { value: "zh-CN", configurable: true });
+    expect(detectBrowserLocale()).toBe(DEFAULT_LOCALE);
+  });
+});

frontend/jest.config.ts

@@ -0,0 +1,21 @@
+// #343 — Jest 설정. next/jest로 SWC 자동 통합.
+
+import type { Config } from "jest";
+import nextJest from "next/jest.js";
+
+const createJestConfig = nextJest({
+  // 테스트 환경의 Next.js 앱 루트
+  dir: "./",
+});
+
+const customConfig: Config = {
+  // jest-dom matchers는 setupFilesAfterEnv로 등록 (Jest framework 로드 후)
+  setupFilesAfterEnv: ["<rootDir>/jest.setup.ts"],
+  testEnvironment: "jsdom",
+  moduleNameMapper: {
+    "^@/(.*)$": "<rootDir>/src/$1",
+  },
+  testPathIgnorePatterns: ["<rootDir>/.next/", "<rootDir>/node_modules/"],
+};
+
+export default createJestConfig(customConfig);

frontend/jest.setup.ts

@@ -0,0 +1,2 @@
+// #343 — Jest setup. @testing-library/jest-dom matchers 확장.
+import "@testing-library/jest-dom";

frontend/next.config.ts

@@ -2,6 +2,14 @@ import type { NextConfig } from "next";
 
 const nextConfig: NextConfig = {
   output: "standalone",
+  // #343 — 외부 이미지 도메인 허용 (next/image)
+  images: {
+    remotePatterns: [
+      { protocol: "https", hostname: "lh3.googleusercontent.com" }, // Google avatar
+      { protocol: "https", hostname: "i.ytimg.com" },               // YouTube thumbnail
+      { protocol: "https", hostname: "yt3.ggpht.com" },             // YouTube channel avatar
+    ],
+  },
 };
 
 export default nextConfig;

frontend/package.json

@@ -6,7 +6,9 @@
     "dev": "next dev",
     "build": "next build",
     "start": "next start",
-    "lint": "eslint"
+    "lint": "eslint",
+    "test": "jest",
+    "test:watch": "jest --watch"
   },
   "dependencies": {
     "@phosphor-icons/react": "^2.1.10",
@@ -22,11 +24,17 @@
   },
   "devDependencies": {
     "@tailwindcss/postcss": "^4",
+    "@testing-library/jest-dom": "^6.9.1",
+    "@testing-library/react": "^16.3.2",
+    "@testing-library/user-event": "^14.6.1",
+    "@types/jest": "^30.0.0",
     "@types/node": "^20",
     "@types/react": "^19",
     "@types/react-dom": "^19",
     "eslint": "^9",
     "eslint-config-next": "16.1.6",
+    "jest": "^30.4.2",
+    "jest-environment-jsdom": "^30.4.1",
     "tailwindcss": "^4",
     "typescript": "^5"
   }

frontend/src/components/MyReviewsList.tsx

@@ -41,8 +41,14 @@ export default function MyReviewsList({
         </button>
       </div>
 
-      <div className="flex gap-1 border-b">
+      {/* #343 — WAI-ARIA Tabs 패턴 */}
+      <div role="tablist" aria-label="내 활동" className="flex gap-1 border-b">
         <button
+          role="tab"
+          id="tab-reviews"
+          aria-selected={tab === "reviews"}
+          aria-controls="panel-reviews"
+          tabIndex={tab === "reviews" ? 0 : -1}
           onClick={() => setTab("reviews")}
           className={`px-3 py-1.5 text-sm font-medium border-b-2 transition-colors ${
             tab === "reviews"
@@ -54,6 +60,11 @@ export default function MyReviewsList({
           리뷰 ({reviews.length})
         </button>
         <button
+          role="tab"
+          id="tab-memos"
+          aria-selected={tab === "memos"}
+          aria-controls="panel-memos"
+          tabIndex={tab === "memos" ? 0 : -1}
           onClick={() => setTab("memos")}
           className={`px-3 py-1.5 text-sm font-medium border-b-2 transition-colors ${
             tab === "memos"
@@ -67,7 +78,8 @@ export default function MyReviewsList({
       </div>
 
       {tab === "reviews" ? (
-        reviews.length === 0 ? (
+        <div role="tabpanel" id="panel-reviews" aria-labelledby="tab-reviews">
+        {reviews.length === 0 ? (
           <p className="text-sm text-gray-500 py-8 text-center">
             아직 작성한 리뷰가 없습니다.
           </p>
@@ -100,9 +112,11 @@ export default function MyReviewsList({
               </button>
             ))}
           </div>
-        )
+        )}
+        </div>
       ) : (
-        memos.length === 0 ? (
+        <div role="tabpanel" id="panel-memos" aria-labelledby="tab-memos">
+        {memos.length === 0 ? (
           <p className="text-sm text-gray-500 py-8 text-center">
             아직 작성한 메모가 없습니다.
           </p>
@@ -137,7 +151,8 @@ export default function MyReviewsList({
               </button>
             ))}
           </div>
-        )
+        )}
+        </div>
       )}
     </div>
   );

frontend/src/components/ReviewSection.tsx

@@ -257,6 +257,9 @@ export default function ReviewSection({ restaurantId }: ReviewSectionProps) {
                     <>
                       <div className="flex items-center gap-2 mb-1">
                         {review.user_avatar_url && (
+                          // eslint-disable-next-line @next/next/no-img-element
+                          // #343 — Google avatar URL은 remotePatterns에 추가됨.
+                          // next/image 전환은 SSR/lazy 효과 미미한 5x5 아바타라 후속에서 일괄 적용.
                           <img
                             src={review.user_avatar_url}
                             alt=""