将 TypeORM 存储库注入 NestJS 服务以进行模拟数据测试

Question

issue 中关于如何执行此操作的讨论很长。

我已经尝试了许多建议的解决方案，但运气不佳。

谁能提供一个具体的例子来说明如何使用注入的存储库和模拟数据来测试服务？

Answer 1

假设我们有一个非常简单的服务，它通过 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);
  }
}

然后您可以使用以下模拟工厂模拟UserRepository（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),
  // ...
}));

使用工厂可确保每次测试都使用新的模拟。

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，您可以为您的（部分）模拟使用以下类型（远非完美，当 jest 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，我在其中插入所有需要的数据并在每次测试运行之前创建架构。所以每个测试都使用相同的数据集，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

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();

Answer 4

您也可以使用测试数据库并在其中插入数据。

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

  beforeEach(async () => {
    moduleRef = await Test.createTestingModule({
      imports: [
        TypeOrmModule.forFeature([Employee]),
        TypeOrmModule.forRoot({
          type: 'postgres',
          host: 'db',
          port: 5432,
          username: 'postgres',
          password: '',
          database: 'test',
          autoLoadEntities: true,
          synchronize: true,
        }),
      ],
      providers: [EmployeesService],
    }).compile();

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

  afterEach(async () => {
    // Free DB connection for next test
    await moduleRef.close();
  });

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

您需要手动创建数据库，例如psql -U postgres -c 'create database test;'。架构同步将自动发生。

Answer 5

从上述想法开始并帮助模拟任何类，我们提出了这个 MockFactory：

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

export class MockFactory {
    static getMock<T>(type: new (...args: any[]) => T, includes?: string[]): MockType<T> {
        const mock: MockType<T> = {};

        Object.getOwnPropertyNames(type.prototype)
            .filter((key: string) => key !== 'constructor' && (!includes || includes.includes(key)))
            .map((key: string) => {
                mock[key] = jest.fn();
            });

        return mock;
    }
}

const module: TestingModule = await Test.createTestingModule({
    providers: [
        {
            provide: getRepositoryToken(MyCustomRepository),
            useValue: MockFactory.getMock(MyCustomRepository)
        }
    ]
}).compile();