chore: Jest에서 Vitest 4.0.15로 마이그레이션

백엔드 테스트 프레임워크를 Jest에서 Vitest로 교체
- vitest 4.0.15 및 unplugin-swc 설치 (NestJS 데코레이터 메타데이터 지원)
- jest, ts-jest, @types/jest 패키지 제거
- vitest.config.ts 및 vitest-e2e.config.ts 생성
- tsconfig.json에 vitest/globals 타입 추가
- 테스트 파일의 jest.fn/spyOn/mock을 vi로 변경
- justfile 테스트 명령어 vitest로 업데이트
- .gemini/styleguide.md 문서 Vitest로 갱신

Author: KubrickCode

.gemini/styleguide.md

@@ -154,7 +154,7 @@ _Function placement in functional files:_
 
 **Recommended libraries**
 
-- Testing: Jest, Playwright
+- Testing: Vitest, Playwright
 - Utility: es-toolkit, dayjs
 - HTTP: ky, @tanstack/query, @apollo/client
 - Form: React Hook Form
@@ -289,15 +289,15 @@ Allow multiple related assertions in one test, but separate tests when verifying
 
 ### Test Framework
 
-Use Jest. Maintain consistency within project.
+Use Vitest. Maintain consistency within project.
 
 ### Structuring
 
 Group methods/features with `describe`, write individual cases with `it`. Can classify scenarios with nested `describe`.
 
 ### Mocking
 
-Utilize Jest's `jest.mock()`, `jest.spyOn()`. Mock external modules at top level, use `mockReturnValue`, `mockImplementation` for per-test behavior changes.
+Utilize Vitest's `vi.mock()`, `vi.spyOn()`. Mock external modules at top level, use `mockReturnValue`, `mockImplementation` for per-test behavior changes.
 
 ### Async Tests
 

justfile

@@ -287,15 +287,15 @@ test target="all" *args:
 
         just setup-testdb
         cd "{{ backend_dir }}"
-        DATABASE_URL="postgres://postgres:postgres@localhost:5432/test?pool_timeout=60" NODE_OPTIONS="--max_old_space_size=8192" PRISMA_CLIENT_ENGINE_TYPE={{ prisma_engine }} pnpm exec jest --runInBand --logHeapUsage --no-compilation-cache --silent=false --passWithNoTests {{ args }}
+        DATABASE_URL="postgres://postgres:postgres@localhost:5432/test?pool_timeout=60" NODE_OPTIONS="--max_old_space_size=8192" PRISMA_CLIENT_ENGINE_TYPE={{ prisma_engine }} pnpm exec vitest run {{ args }}
         ;;
       e2e)
         echo "NodeJS:" $(node -v)
         echo "Prisma Engine:" {{ prisma_engine }}
 
         just setup-testdb
         cd "{{ backend_dir }}"
-        DATABASE_URL="postgres://postgres:postgres@localhost:5432/test?pool_timeout=60" NODE_OPTIONS="--max_old_space_size=8192" PRISMA_CLIENT_ENGINE_TYPE={{ prisma_engine }} pnpm exec jest --config ./jest-e2e.json --runInBand --no-compilation-cache --forceExit --passWithNoTests {{ args }}
+        DATABASE_URL="postgres://postgres:postgres@localhost:5432/test?pool_timeout=60" NODE_OPTIONS="--max_old_space_size=8192" PRISMA_CLIENT_ENGINE_TYPE={{ prisma_engine }} pnpm exec vitest run --config ./vitest-e2e.config.ts {{ args }}
         ;;
       e2e-ui)
         set +x

src/backend/jest-e2e.json

@@ -15,11 +15,10 @@
     "start:debug": "nest start --debug --watch",
     "start:prod": "node dist/src/main",
     "lint": "eslint \"{src,apps,libs,test}/**/*.ts\" --fix",
-    "test": "jest",
-    "test:watch": "jest --watch",
-    "test:cov": "jest --coverage",
-    "test:debug": "node --inspect-brk -r tsconfig-paths/register -r ts-node/register node_modules/.bin/jest --runInBand",
-    "test:e2e": "jest --config ./jest-e2e.json"
+    "test": "vitest run",
+    "test:watch": "vitest",
+    "test:cov": "vitest run --coverage",
+    "test:e2e": "vitest run --config ./vitest-e2e.config.ts"
   },
   "dependencies": {
     "@apollo/server": "4.11.2",
@@ -58,9 +57,9 @@
     "@nestjs/cli": "10.0.0",
     "@nestjs/schematics": "10.0.0",
     "@nestjs/testing": "10.0.0",
+    "@swc/core": "1.15.3",
     "@types/express": "5.0.0",
     "@types/express-session": "1.18.1",
-    "@types/jest": "29.5.2",
     "@types/node": "20.3.1",
     "@types/passport": "1.0.17",
     "@types/passport-discord": "0.1.14",
@@ -70,15 +69,15 @@
     "enforce-unique": "1.3.0",
     "eslint": "9.37.0",
     "eslint-plugin-perfectionist": "4.15.1",
-    "jest": "29.5.0",
     "nestjs-console": "9.0.0",
     "source-map-support": "0.5.21",
     "supertest": "7.0.0",
-    "ts-jest": "29.1.0",
     "ts-loader": "9.4.3",
     "ts-node": "10.9.1",
     "tsconfig-paths": "4.2.0",
     "typescript": "5.1.3",
-    "typescript-eslint": "8.46.0"
+    "typescript-eslint": "8.46.0",
+    "unplugin-swc": "1.5.9",
+    "vitest": "4.0.15"
   }
 }