Added some basic tests for userController

src/user/user.controller.spec.ts

@@ -1,20 +1,111 @@
 import { Test, TestingModule } from '@nestjs/testing';
 import { UserController } from './user.controller';
 import { UserService } from './user.service';
+import { CreateUserDto } from './dto/create-user.dto';
+import { UpdateUserDto } from './dto/update-user.dto';
 
 describe('UserController', () => {
     let controller: UserController;
+    // eslint-disable-next-line @typescript-eslint/no-unused-vars
+    let service: UserService;
+
+    const mockUser = {
+        name: 'Alice',
+        email: 'alice@mail.com',
+        password: 'secret',
+    };
+
+    const mockService = {
+        create: jest.fn(),
+        findAll: jest.fn(),
+        findOne: jest.fn(),
+        update: jest.fn(),
+        remove: jest.fn(),
+    };
 
     beforeEach(async () => {
         const module: TestingModule = await Test.createTestingModule({
             controllers: [UserController],
-            providers: [UserService],
+            providers: [{ provide: UserService, useValue: mockService }],
         }).compile();
 
         controller = module.get<UserController>(UserController);
+        service = module.get<UserService>(UserService);
+
+        jest.clearAllMocks();
+    });
+
+    describe('create()', () => {
+        it('should create and return a user ID', () => {
+            mockService.create.mockReturnValue(1);
+            const dto: CreateUserDto = mockUser;
+            const result = controller.create(dto);
+            expect(result).toBe(1);
+            expect(mockService.create).toHaveBeenCalledWith(dto);
+        });
+
+        it('should handle create failure (mocked error)', () => {
+            mockService.create.mockImplementation(() => {
+                throw new Error('Create failed');
+            });
+            expect(() => controller.create(mockUser)).toThrow('Create failed');
+        });
+    });
+
+    describe('findAll()', () => {
+        it('should return all users', () => {
+            mockService.findAll.mockReturnValue([mockUser]);
+            const result = controller.findAll();
+            expect(result).toEqual([mockUser]);
+        });
+
+        it('should return an empty array when no users exist', () => {
+            mockService.findAll.mockReturnValue([]);
+            const result = controller.findAll();
+            expect(result).toEqual([]);
+        });
+    });
+
+    describe('findOne()', () => {
+        it('should return a user by ID', () => {
+            mockService.findOne.mockReturnValue(mockUser);
+            const result = controller.findOne(1);
+            expect(result).toEqual(mockUser);
+        });
+
+        it('should return "user not found" if user doesn’t exist', () => {
+            mockService.findOne.mockReturnValue(undefined);
+            const result = controller.findOne(999);
+            expect(result).toBe('user not found');
+        });
     });
 
-    it('should be defined', () => {
-        expect(controller).toBeDefined();
+    describe('update()', () => {
+        it('should return success message when update is successful', () => {
+            mockService.update.mockReturnValue(true);
+            const dto: UpdateUserDto = { name: 'Updated' };
+            const result = controller.update(1, dto);
+            expect(result).toBe('user updated');
+        });
+
+        it('should return failure message when update fails', () => {
+            mockService.update.mockReturnValue(false);
+            const result = controller.update(999, { name: 'Nope' });
+            expect(result).toBe('user not updated');
+        });
+    });
+
+    describe('remove()', () => {
+        it('should return success message when user is deleted', () => {
+            mockService.remove.mockReturnValue(true);
+            const result = controller.remove(1);
+            expect(result).toBe('user deleted');
+        });
+
+        it('should return failure message when user is not found', () => {
+            mockService.remove.mockReturnValue(false);
+            const result = controller.remove(999);
+            expect(result).toBe('user could not be deleted');
+        });
     });
 });