NestJs: สร้าง Unit test สำหรับทดสอบ Service ที่ใช้ typeorm + mysql

// task.servic.ts

@Injectable()
export class TaskService {
  constructor(
    @InjectRepository(Task)
    private readonly taskRepository: Repository<Task>,
  ) {}
  ...
}

// src/test-utils/TypeORMMySqlTestingModule.ts

import { TypeOrmModule } from '@nestjs/typeorm';

export const TypeORMMySqlTestingModule = (entities: any[]) => [
  TypeOrmModule.forRoot({
    type: 'mysql',
    host: process.env.MYSQL_HOST || 'localhost',
    port: 3306,
    username: process.env.MYSQL_USERNAME || 'nest',
    password: process.env.MYSQL_PASSWORD || 'nest',
    database: process.env.MYSQL_DATABASE || 'test',
    entities: [...entities],
    synchronize: true,
  })
  TypeOrmModule.forFeature([Task]),
];

// task.service.spac.ts
...
beforeEach(async () => {
    const module: TestingModule = await Test.createTestingModule({
      imports: [...TypeORMMySqlTestingModule([Task])],
      providers: [TaskService],
    }).compile();

    service = module.get<TaskService>(TaskService);
  });
...

$ yarn test src/task/task.service.spec.ts