使用 NestJS 服务单元测试未找到连接“默认”

Question

我目前正在对我的 NestJS 服务进行单元测试。我的实体称为“用户”，我建立了一个基本服务，允许我与 MS SQL 服务器交互，并在我的控制器中建立 GET 和 POST 端点。

虽然我能够模拟服务中使用的 Repository，但我无法在必须调用 getConection() 的方法中建立模拟 getConnection。

当我尝试使用 npm run test:watch 进行单元测试时，我收到了 ConnectionNotFoundError: Connection "default" was not found. 的错误，我已经研究过（实际上，从How to stub EntityManager and Connection in TypeORM with Jest 中提取了很多内容），但这篇文章似乎没有详细说明没有成立，这是我的问题。

无论如何，这是我的相关部分的服务：

import { Injectable } from '@nestjs/common';
import { InjectRepository } from '@nestjs/typeorm';
import { getConnection, Repository } from "typeorm";
import {User} from '../entities/user.entity';


@Injectable()
export class ServiceName {
  constructor(@InjectRepository(User) private usersRepository: Repository<User>) {}

  // Creating and inserting a new user into the database table using Repository
  // unit testing for this one works fine
  async createUserRepository(user: User): Promise<User> {
    const newUser = this.usersRepository.create(user); 
    return await this.usersRepository.save(newUser);
  }

  // Creating and inserting a new user into the database table using QueryBuilder and getConnection
  // unit testing for this one does not work so well 
  async createUserQueryBuilder(user: User): Promise<User> {
    await getConnection()
    .createQueryBuilder()
    .insert()
    .into(User)
    .values([
        user, 
     ])
    .execute();
    return user;  
  }

这是我用于单元测试的 spec.ts 文件：

import { Test, TestingModule } from '@nestjs/testing';
import { ServiceName } from './app_codes_rms_area.service';
import { getRepositoryToken } from '@nestjs/typeorm';
import { User } from '../entities/user.entity';
import { Connection, Repository } from 'typeorm';

describe('service tests', () => {

    const repositoryMockFactory: () => MockType<Repository<any>> = jest.fn(() => ({ 
        create: jest.fn(),
        save: jest.fn(),
        // other functions
    }));

    const mockConnectionFactory = jest.fn(() => ({
        getConnection: jest.fn().mockReturnValue({
            createQueryBuilder: jest.fn().mockReturnThis(),
            getMany: jest.fn().mockReturnValue(allUsers),
            insert: jest.fn().mockReturnThis(),
            into: jest.fn().mockReturnThis(),
            values: jest.fn().mockReturnThis(),
            execute: jest.fn().mockReturnValue(user),
        })
    }));
 
    let service: ServiceName;
    let mockRepository: MockType<Repository<User>>;
    let mockConnection: Connection;

    beforeEach(async () => {
        const module: TestingModule = await Test.createTestingModule({
            providers: [
                ServiceName,
                {
                    provide: getRepositoryToken(User), // a User Repository is injected to the service 
                    useFactory: repositoryMockFactory, // using factory ensures that a new mock is used for every test
                },
                {
                    provide: Connection,
                    useFactory: mockConnectionFactory,
                }
            ],
        }).compile();

        service = module.get<ServiceName>(ServiceName);
        mockRepository = module.get(getRepositoryToken(User));
        mockConnection = module.get<Connection>(Connection);
    });
        it('should create a new user and return it using Repository', async () => {
            // some test that passes using mockRepository
        });

        it('should create a new user and return it using QueryBuilder (with mocked Connection)', async () => {
            expect(await service.createUserQueryBuilder(user)).toEqual(user);
            expect(mockConnection.createQueryBuilder).toBeCalled();
            expect(mockConnection.createQueryBuilder()['insert']).toBeCalled();
            expect(mockConnection.createQueryBuilder()['into']).toBeCalled();
            expect(mockConnection.createQueryBuilder()['values']).toBeCalled();
            expect(mockConnection.createQueryBuilder()['execute']).toBeCalled();
        })

触发以下错误的是第二个测试it('should create a new user and return it using QueryBuilder (with mocked Connection)'：

  ● service tests › Service Functions › should create a new user and return it using QueryBuilder (with mocked Connection)

    ConnectionNotFoundError: Connection "default" was not found.

      at new ConnectionNotFoundError (error/ConnectionNotFoundError.ts:8:9)
      at ConnectionManager.Object.<anonymous>.ConnectionManager.get (connection/ConnectionManager.ts:40:19)
      at Object.getConnection (index.ts:252:35)
      at ServiceName.createUserQueryBuilder (somefile:19:11)
      at Object.it (somefile:134:34)

Answer 1

最简单的解决方案是更改您的 createUserQueryBuilder 方法，如下所示：

async createUserQueryBuilder(user: User): Promise<User> {
  await this.usersRepository
    .createQueryBuilder()
    .insert()
    .into(User)
    .values([
        user, 
     ])
    .execute();
  return user;  
}

然后你可以更新存储库模拟repositoryMockFactory：

const repositoryMockFactory: () => MockType<Repository<any>> = jest.fn(() => ({ 
  create: jest.fn(),
  save: jest.fn(),
  createQueryBuilder: jest.fn().mockReturnThis(),
  getMany: jest.fn().mockReturnValue(allUsers),
  insert: jest.fn().mockReturnThis(),
  into: jest.fn().mockReturnThis(),
  values: jest.fn().mockReturnThis(),
  execute: jest.fn().mockReturnValue(user),
}));

更新：

根据您的要求，您也可以这样做。

更新您的 spec.ts 文件，

import * as typeorm from 'typeorm';

const getConnectionSpy = jest.spyOn(typeorm, 'getConnection');
getConnectionSpy.mockImplementation(() => ({
  createQueryBuilder: jest.fn().mockReturnThis(),
  getMany: jest.fn().mockReturnValue(allUsers),
  insert: jest.fn().mockReturnThis(),
  into: jest.fn().mockReturnThis(),
  values: jest.fn().mockReturnThis(),
  execute: jest.fn().mockReturnValue(user),
}));

请注意，您必须相应地更新您的其他 typeorm 导入。 例如：typeorm.Connection

这只是为了让您了解如何操作。由于我没有对此进行测试，因此可能存在语法错误。