nestjs - SpyOn TypeORM 存储库更改单元测试 NestJS 的返回值

Question

我想对我的 TypeORM 数据库调用进行单元测试。我已经用有效数据模拟了我所有的 TypeORM 存储库。但我想 SpyOn 存储库并更改 TypeORM 的返回值。我怎么做？

import {INestApplication} from '@nestjs/common';
import {Test} from '@nestjs/testing';
import {CommonModule} from '@src/common/common.module';
import {AuthService} from './auth.service';
import {Repository} from 'typeorm';
import {V3User} from '@src/database/entity/user.v3entity';
    
describe('AuthService', () => {
    let service: AuthService;
    let app: INestApplication;
        
    beforeEach(async () => {
        const module = await Test.createTestingModule({
            imports: [CommonModule.forRoot(`${process.env.DEV_ENV}`)],
            providers: [
                AuthService,     
                {provide: 'V3USER_REPOSITORY', useValue: mockRepositoryV3User()},
            ],
        }).compile();
    
        app = module.createNestApplication();
        await app.init();
    
        service = module.get<AuthService>(AuthService);
    });
    

    
    it('test auth service - with non existing user in v3 db', async () => {
                
        jest.spyOn(?????? , 'findOne').mockImplementation(() => undefined);
    
        const res = await service.loginUser("bad token");
    
        await expect(service.tokenBasedAuth('example bad token'))
            .rejects.toThrow('bad token exception');
    });
});

对于正常的测试用例，我像这样模拟数据库:

export const mockRepositoryV3User = () => ({
    metadata: {
        columns: [],
        relations: [],
    },
    findOne: async () =>
        Promise.resolve({
            id: 3,
            email: 'email@example.com',
            first_name: 'david',
            last_name: 'david',
            last_login: '2019-07-15',
            date_joined: '2019-07-15',
        }),
});

Answer 1

好的，在终于开始测试和尝试想法之后，我发现这是一个有效的策略

假设我们已经设置了 PhotoEntity具有基本属性，没有什么特别的(id、名称、描述等)

import { Column, Entity, PrimaryGeneratedColumn } from 'typeorm';

@Entity()
export class Photo {
  @PrimaryGeneratedColumn()
  id: number;

  @Column({ length: 500 })
  name: string;

  @Column('text')
  description: string;

  @Column()
  filename: string;

  @Column('int')
  views: number;

  @Column()
  isPublished: boolean;
}

设置 PhotoService例如以下( super 基本，但它会说明这一点):

import { Injectable } from '@nestjs/common';
import { InjectRepository } from '@nestjs/typeorm';
import { Repository } from 'typeorm';
import { Photo } from './photo.entity';

@Injectable()
export class PhotoService {
  constructor(
    @InjectRepository(Photo)
    private readonly photoRepository: Repository<Photo>,
  ) {}

  async findAll(): Promise<Photo[]> {
    return await this.photoRepository.find();
  }
}

我们可以useClass: Repository这样我们就不必做任何繁重的设置存储库类以用于测试(存储库是从 TypeORM 包中导入的。然后我们可以从模块中获取存储库并将其保存为一个值以便于像这样模拟并设置我们的测试:

import { Test, TestingModule } from '@nestjs/testing';
import { PhotoService } from './photo.service';
import { getRepositoryToken } from '@nestjs/typeorm';
import { Photo } from './photo.entity';
import { Repository } from 'typeorm';

describe('PhotoService', () => {
  let service: PhotoService;
  // declaring the repo variable for easy access later
  let repo: Repository<Photo>;

  beforeEach(async () => {
    const module: TestingModule = await Test.createTestingModule({
      providers: [
        PhotoService,
        {
          // how you provide the injection token in a test instance
          provide: getRepositoryToken(Photo),
          // as a class value, Repository needs no generics
          useClass: Repository,
        },
      ],
    }).compile();

    service = module.get<PhotoService>(PhotoService);
    // Save the instance of the repository and set the correct generics
    repo = module.get<Repository<Photo>>(getRepositoryToken(Photo));
  });

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

  it('should return for findAll', async () => {
    // mock file for reuse
    const testPhoto: Photo =  {
      id: 'a47ecdc2-77d6-462f-9045-c440c5e4616f',
      name: 'hello',
      description: 'the description',
      isPublished: true,
      filename: 'testFile.png',
      views: 5,
    };
    // notice we are pulling the repo variable and using jest.spyOn with no issues
    jest.spyOn(repo, 'find').mockResolvedValueOnce([testPhoto]);
    expect(await service.findAll()).toEqual([testPhoto]);
  });
});

针对指定文件或针对所有测试运行测试

▶ npm run test -- photo.service

> nestjs-playground@0.0.1 test ~/Documents/code/nestjs-playground
> jest "photo.service"

 PASS  src/photo/photo.service.spec.ts
  PhotoService
    ✓ should be defined (17ms)
    ✓ should return for findAll (4ms)  < -- test passes with no problem

Test Suites: 1 passed, 1 total
Tests:       2 passed, 2 total
Snapshots:   0 total
Time:        3.372s, estimated 4s
Ran all test suites matching /photo.service/i.