feat(products): vitest 도입 + 제품 접근 확장 로직 (music tier 하위 호환)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

lib/__tests__/product-access.test.ts

@@ -0,0 +1,24 @@
+import { describe, it, expect } from 'vitest';
+import { expandProductAccess, MUSIC_PRODUCT_CHAIN } from '@/lib/product-access';
+
+describe('expandProductAccess', () => {
+  it('일반 제품은 자기 자신만 반환', () => {
+    expect(expandProductAccess(['lotto_tool'])).toEqual(['lotto_tool']);
+  });
+  it('music_pro는 starter를 포함', () => {
+    expect(expandProductAccess(['music_pro']).sort()).toEqual(['music_pro', 'music_starter'].sort());
+  });
+  it('music_master는 전 tier 포함', () => {
+    expect(expandProductAccess(['music_master']).sort()).toEqual(
+      ['music_master', 'music_pro', 'music_starter'].sort(),
+    );
+  });
+  it('중복 입력은 중복 없이 반환', () => {
+    expect(expandProductAccess(['music_pro', 'music_starter']).sort()).toEqual(
+      ['music_pro', 'music_starter'].sort(),
+    );
+  });
+  it('빈 입력은 빈 배열', () => {
+    expect(expandProductAccess([])).toEqual([]);
+  });
+});

lib/product-access.ts

@@ -0,0 +1,17 @@
+/**
+ * orders 기반 제품 접근 확장.
+ * 음악 팩 상위 tier는 하위 tier 파일도 포함(하위 호환) — 신규 제품은 1:1.
+ */
+export const MUSIC_PRODUCT_CHAIN: Record<string, string[]> = {
+  music_starter: ['music_starter'],
+  music_pro: ['music_pro', 'music_starter'],
+  music_master: ['music_master', 'music_pro', 'music_starter'],
+};
+
+export function expandProductAccess(paidProductIds: string[]): string[] {
+  const out = new Set<string>();
+  for (const id of paidProductIds) {
+    for (const expanded of MUSIC_PRODUCT_CHAIN[id] ?? [id]) out.add(expanded);
+  }
+  return Array.from(out);
+}

package.json

@@ -6,7 +6,8 @@
     "dev": "next dev",
     "build": "next build",
     "start": "next start",
-    "lint": "eslint"
+    "lint": "eslint",
+    "test": "vitest run"
   },
   "dependencies": {
     "@anthropic-ai/sdk": "^0.79.0",
@@ -39,6 +40,7 @@
     "eslint": "^9",
     "eslint-config-next": "16.1.6",
     "tailwindcss": "^4",
-    "typescript": "^5"
+    "typescript": "^5",
+    "vitest": "^4.1.8"
   }
 }

vitest.config.ts

@@ -0,0 +1,7 @@
+import { defineConfig } from 'vitest/config';
+import path from 'path';
+
+export default defineConfig({
+  test: { include: ['lib/**/*.test.ts'] },
+  resolve: { alias: { '@': path.resolve(__dirname, '.') } },
+});