test(admin): add unit tests for AdminService with mocked repositories

backend/src/admin/admin.service.spec.ts

@@ -0,0 +1,58 @@
+import { Test, TestingModule } from "@nestjs/testing";
+import { CategoriesRepository } from "../categories/repositories/categories.repository";
+import { ContentsRepository } from "../contents/repositories/contents.repository";
+import { UsersRepository } from "../users/repositories/users.repository";
+import { AdminService } from "./admin.service";
+
+describe("AdminService", () => {
+	let service: AdminService;
+	let _usersRepository: UsersRepository;
+	let _contentsRepository: ContentsRepository;
+	let _categoriesRepository: CategoriesRepository;
+
+	const mockUsersRepository = {
+		countAll: jest.fn(),
+	};
+
+	const mockContentsRepository = {
+		count: jest.fn(),
+	};
+
+	const mockCategoriesRepository = {
+		countAll: jest.fn(),
+	};
+
+	beforeEach(async () => {
+		const module: TestingModule = await Test.createTestingModule({
+			providers: [
+				AdminService,
+				{ provide: UsersRepository, useValue: mockUsersRepository },
+				{ provide: ContentsRepository, useValue: mockContentsRepository },
+				{ provide: CategoriesRepository, useValue: mockCategoriesRepository },
+			],
+		}).compile();
+
+		service = module.get<AdminService>(AdminService);
+		_usersRepository = module.get<UsersRepository>(UsersRepository);
+		_contentsRepository = module.get<ContentsRepository>(ContentsRepository);
+		_categoriesRepository =
+			module.get<CategoriesRepository>(CategoriesRepository);
+	});
+
+	it("should return stats", async () => {
+		mockUsersRepository.countAll.mockResolvedValue(10);
+		mockContentsRepository.count.mockResolvedValue(20);
+		mockCategoriesRepository.countAll.mockResolvedValue(5);
+
+		const result = await service.getStats();
+
+		expect(result).toEqual({
+			users: 10,
+			contents: 20,
+			categories: 5,
+		});
+		expect(mockUsersRepository.countAll).toHaveBeenCalled();
+		expect(mockContentsRepository.count).toHaveBeenCalledWith({});
+		expect(mockCategoriesRepository.countAll).toHaveBeenCalled();
+	});
+});