将TypeORM存储库注入NestJS服务以进行模拟数据测试

Question

有关如何在本期中执行此操作的讨论很长时间。

我已经尝试了许多建议的解决方案，但是运气并不好。

谁能提供一个具体示例，说明如何使用注入的存储库和模拟数据测试服务？

Answer 1

假设我们有一个非常简单的服务，该服务通过id查找用户实体：

export class UserService {
  constructor(@InjectRepository(UserEntity) private userRepository: Repository<UserEntity>) {
  }

  async findUser(userId: string): Promise<UserEntity> {
    return this.userRepository.findOne(userId);
  }
}

然后，您可以UserRepository使用以下模拟工厂模拟（根据需要添加更多方法）：

// @ts-ignore
export const repositoryMockFactory: () => MockType<Repository<any>> = jest.fn(() => ({
  findOne: jest.fn(entity => entity),
  // ...
}));

使用工厂可确保为每个测试使用新的模拟。

describe('UserService', () => {
  let service: UserService;
  let repositoryMock: MockType<Repository<UserEntity>>;

  beforeEach(async () => {
    const module: TestingModule = await Test.createTestingModule({
      providers: [
        UserService,
        // Provide your mock instead of the actual repository
        { provide: getRepositoryToken(UserEntity), useFactory: repositoryMockFactory },
      ],
    }).compile();
    service = module.get<UserService>(UserService);
    repositoryMock = module.get(getRepositoryToken(UserEntity));
  });

  it('should find a user', async () => {
    const user = {name: 'Alni', id: '123'};
    // Now you can control the return value of your mock's methods
    repositoryMock.findOne.mockReturnValue(user);
    expect(service.findUser(user.id)).toEqual(user);
    // And make assertions on how often and with what params your mock's methods are called
    expect(repositoryMock.findOne).toHaveBeenCalledWith(user.id);
  });
});

为了类型安全和舒适，您可以为模拟使用以下类型（远非完美，当笑话本身在即将发布的主要版本中开始使用typescript时，可能会有更好的解决方案）：

export type MockType<T> = {
  [P in keyof T]: jest.Mock<{}>;
};

Answer 2

我的解决方案使用 sqlite 内存数据库，我在每次测试运行之前插入所有需要的数据并创建模式。因此，每个测试都使用相同的数据集进行计数，您不必模拟任何 TypeORM 方法：

import { Test, TestingModule } from "@nestjs/testing";
import { CompanyInfo } from '../../src/company-info/company-info.entity';
import { CompanyInfoService } from "../../src/company-info/company-info.service";
import { Repository, createConnection, getConnection, getRepository } from "typeorm";
import { getRepositoryToken } from "@nestjs/typeorm";

describe('CompanyInfoService', () => {
  let service: CompanyInfoService;
  let repository: Repository<CompanyInfo>;
  let testingModule: TestingModule;

  const testConnectionName = 'testConnection';

  beforeEach(async () => {
    testingModule = await Test.createTestingModule({
      providers: [
        CompanyInfoService,
        {
          provide: getRepositoryToken(CompanyInfo),
          useClass: Repository,
        },
      ],
    }).compile();

    let connection = await createConnection({
        type: "sqlite",
        database: ":memory:",
        dropSchema: true,
        entities: [CompanyInfo],
        synchronize: true,
        logging: false,
        name: testConnectionName
    });    

    repository = getRepository(CompanyInfo, testConnectionName);
    service = new CompanyInfoService(repository);

    return connection;
  });

  afterEach(async () => {
    await getConnection(testConnectionName).close()
  });  

  it('should be defined', () => {
    expect(service).toBeDefined();
  });

  it('should return company info for findOne', async () => {
    // prepare data, insert them to be tested
    const companyInfoData: CompanyInfo = {
      id: 1,
    };

    await repository.insert(companyInfoData);

    // test data retrieval itself
    expect(await service.findOne()).toEqual(companyInfoData);
  });
});

我在这里得到了启发：https : //gist.github.com/Ciantic/be6a8b8ca27ee15e2223f642b5e01549

Answer 3

与其他框架中的最佳实践类似，您可以使用测试数据库而不是模拟数据库。

describe('EmployeesService', () => {
  let employeesService: EmployeesService;
  let moduleRef: TestingModule;

  beforeEach(async () => {
    moduleRef = await Test.createTestingModule({
      imports: [
        TypeOrmModule.forRoot({
          type: 'postgres',
          url: 'postgres://postgres:@db:5432/test', // read this from env
          autoLoadEntities: true,
          synchronize: true,
          dropSchema: true,
        }),
      ],
      providers: [EmployeesService],
    }).compile();

    employeesService = moduleRef.get<EmployeesService>(EmployeesService);
  });

  afterEach(async () => {
    await moduleRef.close();
  });

  describe('findOne', () => {
    it('returns empty array', async () => {
      expect(await employeesService.findAll()).toStrictEqual([]);
    });
  });
});

解析器规范中的真实示例： https: //github.com/thisismydesign/nestjs-starter

最后用typeorm@0.3.7和进行测试@nestjs/typeorm@9.0.0。

Answer 4

我还发现这对我有用：

export const mockRepository = jest.fn(() => ({
  metadata: {
    columns: [],
    relations: [],
  },
}));

和

const module: TestingModule = await Test.createTestingModule({
      providers: [{ provide: getRepositoryToken(Entity), useClass: mockRepository }],
    }).compile();