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如何用笑话来嘲笑和刺探猫鼬。在NestJS的提供者中连接

nestjs jestjs mongoose

Hantsy · 技术社区 · 6 年前

我定义了一个自定义的特定数据库 Module 通过Mongoose API连接MongoDB。

完整的代码是 here .

  {
    provide: DATABASE_CONNECTION,
    useFactory: (dbConfig: ConfigType<typeof mongodbConfig>): Connection =>
      createConnection(dbConfig.uri, {
        useNewUrlParser: true,
        useUnifiedTopology: true,
        //see: https://mongoosejs.com/docs/deprecations.html#findandmodify
        useFindAndModify: false
      }),
    inject: [mongodbConfig.KEY],
  },

在为这个提供程序编写测试时,我想确认数据库连接是否已定义并监视 connect 方法来验证调用的参数。

我真的需要手动模拟功能,但有 an issue which is closed suddenly .

更新: 我试着用 mocked 从…起 ts-jest ,但它不起作用。

describe('DatabaseProviders(Connectoin)', () => {
  let conn: any;

  jest.mock('mongoose', () => {
    return { createConnection: jest.fn() };
  })

  beforeEach(() => {
    // provide a mock implementation for the mocked createConnection:
    mocked(createConnection).mockImplementation((uri: any, options: any) => {
      return {} as any
    });
  });

  beforeEach(async () => {
    const module: TestingModule = await Test.createTestingModule({
      providers: [...databaseProviders],
    }).compile();

    conn = module.get<Connection>(DATABASE_CONNECTION);
  });

  afterEach(() => {
    mocked(createConnection).mockClear();
  });

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

  it('connect is called', () => {
    expect(conn).toBeDefined();
    expect(mocked(createConnection).mock.calls.length).toBe(1)
  })

});

运行应用程序时,它会抱怨:

TypeError: utils_1.mocked(...).mockImplementation is not a function

0 回复 | 直到 6 年前

Hantsy 5 年前

在研究了一些资源并阅读了Jest文档后,我自己解决了这个问题。


jest.mock('mongoose', () => ({
    createConnection: jest.fn().mockImplementation(
      (uri:any, options:any)=>({} as any)
      ),
    Connection: jest.fn()
  }))

import { ConfigModule } from '@nestjs/config';
import { Test, TestingModule } from '@nestjs/testing';
import { Connection, createConnection } from 'mongoose';
import mongodbConfig from '../config/mongodb.config';
import { databaseConnectionProviders } from './database-connection.providers';
import { DATABASE_CONNECTION } from './database.constants';

describe('DatabaseConnectionProviders', () => {
  let conn: any;

  beforeEach(async () => {
    const module: TestingModule = await Test.createTestingModule({
      imports: [ConfigModule.forFeature(mongodbConfig)],
      providers: [...databaseConnectionProviders],
    }).compile();

    conn = module.get<Connection>(DATABASE_CONNECTION);
  });



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

  it('connect is called', () => {
    //expect(conn).toBeDefined();
    //expect(createConnection).toHaveBeenCalledTimes(1); // it is 2 here. why?
    expect(createConnection).toHaveBeenCalledWith("mongodb://localhost/blog", {
      useNewUrlParser: true,
      useUnifiedTopology: true,
      //see: https://mongoosejs.com/docs/deprecations.html#findandmodify
      useFindAndModify: false
    });
  })

});

检查完整的代码 here .