Suites

import { TestBed, type Mocked } from '@suites/unit';

describe('User Service', () => {
  let userService: UserService; // The unit we are testing
  let userApi: Mocked<UserApi>; // The dependencies we are mocking
  let database: Mocked<Database>;

  beforeAll(async () => {
    // Create an isolated test env for the unit
    const { unit, unitRef } = await TestBed.solitary(UserService).compile();

    userService = unit;    
    // Retrieve the unit's dependency mocks - automatically generated
    userApi = unitRef.get(UserApi);
    database = unitRef.get(Database);
  });

  // ✅ Test test test
  it('should generate a random user and save to the database', async () => {
    userApi.getRandom.mockResolvedValue({id: 1, name: 'John'} as User);
    await userService.generateRandomUser();
    expect(database.saveUser).toHaveBeenCalledWith(userFixture);
  });
});

// THE MANUAL WAY
// (Similar complexity exists in NestJS, InversifyJS, etc.)

import { UserService } from './user-service';
import { UserApi } from './user-api';
import { Database } from './database';

describe('User Service', () => {
  let userService: UserService;
  let userApi: any; // ❌ Lost type safety!
  let database: any;

  beforeAll(async () => {
    // 🔧 Manually create mocks for each dependency
    userApi = {
      getRandom: jest.fn(),
      // Missing methods? Who knows? No compile-time checks!
    };

    database = {
      saveUser: jest.fn(),
      // What other methods exist? ¯\_(ツ)_/¯
    };

    // Manual wiring - boilerplate for every test
    userService = new UserService(userApi, database);
  });

  it('should generate a random user and save to the database', async () => {
    userApi.getRandom.mockResolvedValue({id: 1, name: 'John'} as User);
    await userService.generateRandomUser();
    expect(database.saveUser).toHaveBeenCalledWith(userFixture);
  });
}