diff --git a/packages/backend/test/unit/entities/DriveFileEntityService.ts b/packages/backend/test/unit/entities/DriveFileEntityService.ts
new file mode 100644
index 0000000000..2e416326ee
--- /dev/null
+++ b/packages/backend/test/unit/entities/DriveFileEntityService.ts
@@ -0,0 +1,227 @@
+/*
+ * SPDX-FileCopyrightText: syuilo and misskey-project
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+process.env.NODE_ENV = 'test';
+
+import { afterAll, beforeAll, beforeEach, describe, expect, jest, test } from '@jest/globals';
+import { Test } from '@nestjs/testing';
+import type { TestingModule } from '@nestjs/testing';
+import type { DriveFilesRepository, DriveFoldersRepository, UsersRepository } from '@/models/_.js';
+import { GlobalModule } from '@/GlobalModule.js';
+import { CoreModule } from '@/core/CoreModule.js';
+import { DriveFileEntityService } from '@/core/entities/DriveFileEntityService.js';
+import { DriveFolderEntityService } from '@/core/entities/DriveFolderEntityService.js';
+import { UserEntityService } from '@/core/entities/UserEntityService.js';
+import { DI } from '@/di-symbols.js';
+import { genAidx } from '@/misc/id/aidx.js';
+import { secureRndstr } from '@/misc/secure-rndstr.js';
+
+const describeBenchmark = process.env.RUN_BENCHMARKS === '1' ? describe : describe.skip;
+
+describe('DriveFileEntityService', () => {
+	let app: TestingModule;
+	let service: DriveFileEntityService;
+	let driveFolderEntityService: DriveFolderEntityService;
+	let driveFilesRepository: DriveFilesRepository;
+	let driveFoldersRepository: DriveFoldersRepository;
+	let usersRepository: UsersRepository;
+	let idCounter = 0;
+
+	const userEntityServiceMock = {
+		packMany: jest.fn(async (users: Array<string | { id: string }>) => {
+			return users.map(u => ({
+				id: typeof u === 'string' ? u : u.id,
+				username: 'user',
+			}));
+		}),
+		pack: jest.fn(async (user: string | { id: string }) => {
+			return {
+				id: typeof user === 'string' ? user : user.id,
+				username: 'user',
+			};
+		}),
+	};
+
+	const nextId = () => genAidx(Date.now() + (idCounter++));
+
+	const createUser = async () => {
+		const un = secureRndstr(16);
+		const id = nextId();
+		await usersRepository.insert({
+			id,
+			username: un,
+			usernameLower: un.toLowerCase(),
+		});
+		return usersRepository.findOneByOrFail({ id });
+	};
+
+	const createFolder = async (name: string, parentId: string | null) => {
+		const id = nextId();
+		await driveFoldersRepository.insert({
+			id,
+			name,
+			userId: null,
+			parentId,
+		});
+		return driveFoldersRepository.findOneByOrFail({ id });
+	};
+
+	const createFile = async (folderId: string | null, userId: string | null) => {
+		const id = nextId();
+		await driveFilesRepository.insert({
+			id,
+			userId,
+			userHost: null,
+			md5: secureRndstr(32),
+			name: `file-${id}`,
+			type: 'text/plain',
+			size: 1,
+			comment: null,
+			blurhash: null,
+			properties: {},
+			storedInternal: true,
+			url: `https://example.com/${id}`,
+			thumbnailUrl: null,
+			webpublicUrl: null,
+			webpublicType: null,
+			accessKey: null,
+			thumbnailAccessKey: null,
+			webpublicAccessKey: null,
+			uri: null,
+			src: null,
+			folderId,
+			isSensitive: false,
+			maybeSensitive: false,
+			maybePorn: false,
+			isLink: false,
+			requestHeaders: null,
+			requestIp: null,
+		});
+		return driveFilesRepository.findOneByOrFail({ id });
+	};
+
+	beforeAll(async () => {
+		const moduleBuilder = Test.createTestingModule({
+			imports: [GlobalModule, CoreModule],
+		});
+		moduleBuilder.overrideProvider(UserEntityService).useValue(userEntityServiceMock as any);
+
+		app = await moduleBuilder.compile();
+		await app.init();
+		app.enableShutdownHooks();
+
+		service = app.get<DriveFileEntityService>(DriveFileEntityService);
+		driveFolderEntityService = app.get<DriveFolderEntityService>(DriveFolderEntityService);
+		driveFilesRepository = app.get<DriveFilesRepository>(DI.driveFilesRepository);
+		driveFoldersRepository = app.get<DriveFoldersRepository>(DI.driveFoldersRepository);
+		usersRepository = app.get<UsersRepository>(DI.usersRepository);
+	});
+
+	beforeEach(() => {
+		userEntityServiceMock.packMany.mockClear();
+		userEntityServiceMock.pack.mockClear();
+	});
+
+	afterAll(async () => {
+		await app.close();
+	});
+
+	describe('pack', () => {
+		test('detail: false', async () => {
+			const user = await createUser();
+			const folder = await createFolder('pack-root', null);
+			const file = await createFile(folder.id, user.id);
+
+			const packed = await service.pack(file, { detail: false, self: true }) as any;
+			expect(packed.id).toBe(file.id);
+			expect(packed.folder).toBeNull();
+			expect(packed.user).toBeNull();
+			expect(packed.userId).toBeNull();
+		});
+
+		test('detail: true', async () => {
+			const folder = await createFolder('pack-parent', null);
+			const child = await createFolder('pack-child', folder.id);
+			const file = await createFile(child.id, null);
+
+			const packed = await service.pack(file, { detail: true, self: true }) as any;
+			expect(packed.folder?.id).toBe(child.id);
+			expect(packed.folder?.parent?.id).toBe(folder.id);
+		});
+	});
+
+	describe('packNullable', () => {
+		test('returns null for missing', async () => {
+			const packed = await service.packNullable('non-existent' as any, { detail: false });
+			expect(packed).toBeNull();
+		});
+
+		test('uses packedUser hint when withUser', async () => {
+			const user = await createUser();
+			const file = await createFile(null, user.id);
+
+			const packed = await service.packNullable(file, { withUser: true, self: true }, {
+				packedUser: { id: user.id, username: 'hint' } as any,
+			});
+			expect(packed?.user?.id).toBe(user.id);
+			expect(packed?.user?.username).toBe('hint');
+		});
+	});
+
+	describe('packMany', () => {
+		test('withUser: true uses deduped packMany', async () => {
+			const user = await createUser();
+			const fileA = await createFile(null, user.id);
+			const fileB = await createFile(null, user.id);
+
+			const packed = await service.packMany([fileA, fileB], { withUser: true, self: true });
+			expect(packed.length).toBe(2);
+			expect(userEntityServiceMock.packMany).toHaveBeenCalledTimes(1);
+			expect(userEntityServiceMock.packMany.mock.calls[0]?.[0]?.length).toBe(1);
+			expect(packed[0]?.user?.id).toBe(user.id);
+		});
+
+		test('detail: true packs folder', async () => {
+			const folder = await createFolder('packmany-root', null);
+			const file = await createFile(folder.id, null);
+
+			const packed = await service.packMany([file], { detail: true, self: true });
+			expect(packed[0]?.folder?.id).toBe(folder.id);
+			expect(packed[0]?.folder?.parent).toBeUndefined();
+		});
+
+		test('detail: true uses DriveFolderEntityService pack', async () => {
+			const folder = await createFolder('packmany-folder', null);
+			const file = await createFile(folder.id, null);
+			const packSpy = jest.spyOn(driveFolderEntityService, 'pack');
+
+			await service.packMany([file], { detail: true, self: true });
+			expect(packSpy).toHaveBeenCalled();
+			packSpy.mockRestore();
+		});
+	});
+
+	describeBenchmark('benchmark', () => {
+		test('packMany', async () => {
+			const user = await createUser();
+			const folders = [];
+			for (let i = 0; i < 100; i++) {
+				folders.push(await createFolder(`bench-${i}`, null));
+			}
+			const files = [];
+			for (const folder of folders) {
+				for (let j = 0; j < 20; j++) {
+					files.push(await createFile(folder.id, user.id));
+				}
+			}
+
+			const start = Date.now();
+			await service.packMany(files, { detail: true, withUser: true, self: true });
+			const elapsed = Date.now() - start;
+
+			console.log(`DriveFileEntityService.packMany benchmark: ${elapsed}ms`);
+		});
+	});
+});
diff --git a/packages/backend/test/unit/entities/DriveFolderEntityService.ts b/packages/backend/test/unit/entities/DriveFolderEntityService.ts
new file mode 100644
index 0000000000..81399cdc54
--- /dev/null
+++ b/packages/backend/test/unit/entities/DriveFolderEntityService.ts
@@ -0,0 +1,169 @@
+/*
+ * SPDX-FileCopyrightText: syuilo and misskey-project
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+process.env.NODE_ENV = 'test';
+
+import { afterAll, beforeAll, describe, expect, test } from '@jest/globals';
+import { Test } from '@nestjs/testing';
+import type { TestingModule } from '@nestjs/testing';
+import type { DriveFilesRepository, DriveFoldersRepository } from '@/models/_.js';
+import { GlobalModule } from '@/GlobalModule.js';
+import { CoreModule } from '@/core/CoreModule.js';
+import { DriveFolderEntityService } from '@/core/entities/DriveFolderEntityService.js';
+import { DI } from '@/di-symbols.js';
+import { genAidx } from '@/misc/id/aidx.js';
+import { secureRndstr } from '@/misc/secure-rndstr.js';
+
+const describeBenchmark = process.env.RUN_BENCHMARKS === '1' ? describe : describe.skip;
+
+describe('DriveFolderEntityService', () => {
+	let app: TestingModule;
+	let service: DriveFolderEntityService;
+	let driveFoldersRepository: DriveFoldersRepository;
+	let driveFilesRepository: DriveFilesRepository;
+	let idCounter = 0;
+
+	const nextId = () => genAidx(Date.now() + (idCounter++));
+
+	const createFolder = async (name: string, parentId: string | null) => {
+		const id = nextId();
+		await driveFoldersRepository.insert({
+			id,
+			name,
+			userId: null,
+			parentId,
+		});
+		return driveFoldersRepository.findOneByOrFail({ id });
+	};
+
+	const createFile = async (folderId: string | null) => {
+		const id = nextId();
+		await driveFilesRepository.insert({
+			id,
+			userId: null,
+			userHost: null,
+			md5: secureRndstr(32),
+			name: `file-${id}`,
+			type: 'text/plain',
+			size: 1,
+			comment: null,
+			blurhash: null,
+			properties: {},
+			storedInternal: true,
+			url: `https://example.com/${id}`,
+			thumbnailUrl: null,
+			webpublicUrl: null,
+			webpublicType: null,
+			accessKey: null,
+			thumbnailAccessKey: null,
+			webpublicAccessKey: null,
+			uri: null,
+			src: null,
+			folderId,
+			isSensitive: false,
+			maybeSensitive: false,
+			maybePorn: false,
+			isLink: false,
+			requestHeaders: null,
+			requestIp: null,
+		});
+	};
+
+	beforeAll(async () => {
+		app = await Test.createTestingModule({
+			imports: [GlobalModule, CoreModule],
+		}).compile();
+		await app.init();
+		app.enableShutdownHooks();
+
+		service = app.get<DriveFolderEntityService>(DriveFolderEntityService);
+		driveFoldersRepository = app.get<DriveFoldersRepository>(DI.driveFoldersRepository);
+		driveFilesRepository = app.get<DriveFilesRepository>(DI.driveFilesRepository);
+	});
+
+	afterAll(async () => {
+		await app.close();
+	});
+
+	describe('pack', () => {
+		test('detail: false', async () => {
+			const root = await createFolder('root', null);
+			const child = await createFolder('child', root.id);
+
+			const packed = await service.pack(child, { detail: false }) as any;
+			expect(packed.id).toBe(child.id);
+			expect(packed.parentId).toBe(root.id);
+			expect(packed.parent).toBeUndefined();
+			expect(packed.foldersCount).toBeUndefined();
+			expect(packed.filesCount).toBeUndefined();
+		});
+
+		test('detail: true', async () => {
+			const root = await createFolder('root-detail', null);
+			const child = await createFolder('child-detail', root.id);
+			await createFolder('grandchild-detail', child.id);
+			await createFile(child.id);
+			await createFile(child.id);
+
+			const packed = await service.pack(child, { detail: true }) as any;
+			expect(packed.id).toBe(child.id);
+			expect(packed.foldersCount).toBe(1);
+			expect(packed.filesCount).toBe(2);
+			expect(packed.parent?.id).toBe(root.id);
+			expect(packed.parent?.parent).toBeUndefined();
+		});
+
+		test('detail: true reaches root for deep hierarchy', async () => {
+			const root = await createFolder('root-deep', null);
+			const level1 = await createFolder('level-1', root.id);
+			const level2 = await createFolder('level-2', level1.id);
+			const level3 = await createFolder('level-3', level2.id);
+			const level4 = await createFolder('level-4', level3.id);
+			const level5 = await createFolder('level-5', level4.id);
+
+			const packed = await service.pack(level5, { detail: true }) as any;
+			expect(packed.id).toBe(level5.id);
+			expect(packed.parent?.id).toBe(level4.id);
+			expect(packed.parent?.parent?.id).toBe(level3.id);
+			expect(packed.parent?.parent?.parent?.id).toBe(level2.id);
+			expect(packed.parent?.parent?.parent?.parent?.id).toBe(level1.id);
+			expect(packed.parent?.parent?.parent?.parent?.parent?.id).toBe(root.id);
+			expect(packed.parent?.parent?.parent?.parent?.parent?.parent).toBeUndefined();
+		});
+	});
+
+	describe('packMany', () => {
+		test('preserves order and packs parents', async () => {
+			const root = await createFolder('root-many', null);
+			const childA = await createFolder('child-a', root.id);
+			const childB = await createFolder('child-b', root.id);
+			await createFile(childA.id);
+
+			const packed = await service.packMany([childB, childA], { detail: true }) as any;
+			expect(packed[0].id).toBe(childB.id);
+			expect(packed[1].id).toBe(childA.id);
+			expect(packed[0].parent?.id).toBe(root.id);
+			expect(packed[1].parent?.id).toBe(root.id);
+			expect(packed[0].filesCount).toBe(0);
+			expect(packed[1].filesCount).toBe(1);
+		});
+	});
+
+	describeBenchmark('benchmark', () => {
+		test('packMany', async () => {
+			const root = await createFolder('bench-root', null);
+			const folders = [];
+			for (let i = 0; i < 200; i++) {
+				folders.push(await createFolder(`bench-${i}`, root.id));
+			}
+
+			const start = Date.now();
+			await service.packMany(folders, { detail: true });
+			const elapsed = Date.now() - start;
+			 
+			console.log(`DriveFolderEntityService.packMany benchmark: ${elapsed}ms`);
+		});
+	});
+});