如何使用 Jest 对 typeorm getRepository 进行单元测试？

Posted 2023-03-13

【中文标题】如何使用 Jest 对 typeorm getRepository 进行单元测试？

【英文标题】：How to unit test typeorm getRepository with Jest?

【发布时间】：2021-08-08 00:36:21

【问题描述】：

我正在使用带有 typeorm 的 typescript，并且我有一个这样的存储库：

import  EntityRepository, getRepository, createQueryBuilder  from 'typeorm';


@EntityRepository()
export default class Repo 
  async getSomething(): Promise<Result> 
    const schemaQuery = getRepository(SomeModel)
      .createQueryBuilder('sm')
      .select(...)
      .where(...);
      .....

我的测试文件是这样的

import * as typeorm from 'typeorm';
import Repo from '../../../../src/repositories/Repo';

describe(
  'test',
  () => 
    let repo: Repo;
    beforeEach(() => 
      repo = new Repo();
    );
    test('getSomething works', async () => 
      jest.spyOn(typeorm, 'getRepository').mockImplementation(() => ( // typescript wants me to implement all properties of getRepository which i dont want
        createQueryBuilder: jest.fn(),
      ));
        ...
    );
  ,
);

我如何直接从仍然符合 typescript 类型检查的 typeorm 模拟 getRepository？

【问题讨论】：

我有类似的问题要测试自定义存储库，***.com/questions/67580233/…

【参考方案1】：

我刚刚遇到了这个问题，我实际上使用您的代码作为我的解决方案的基础。请试试这个：

    jest.spyOn(typeorm, "getRepository").mockImplementation(() => 
      const original = jest.requireActual("typeorm");
     // You need all functions used in your Query builder  
     return 
        ...original,
        createQueryBuilder: jest.fn().mockImplementation(() => (
          subQuery: jest.fn().mockReturnThis() as unknown,
          from: jest.fn().mockReturnThis() as unknown,
          where: jest.fn().mockReturnThis() as unknown,
          select: jest.fn().mockReturnThis() as unknown,
          getQuery: jest.fn().mockReturnThis() as unknown,
          setParameter: jest.fn().mockReturnThis() as unknown,
          getMany: jest
            .fn()
            .mockResolvedValue(expected) as unknown,
        )),
      ;
    );

【讨论】：

如何模拟其中包含 where 子句的 typeorm getRepository 查找方法？例如：userRepo.find( where: "userId": 5 );

您可能需要将getMany 字段替换为一个笑话函数并更改解析值

【参考方案2】：

当我尝试这样做时，我收到以下错误

 TypeError: Cannot redefine property: getRepository
        at Function.defineProperty (<anonymous>)

      64 |      as unknown as Installation;
      65 |
    > 66 |     jest.spyOn(typeorm, 'getRepository').mockImplementation(() => 
         |          ^
      67 |       const original = jest.requireActual('typeorm');
      68 |       // You need all functions used in your Query builder
      69 |       return 

看看我的sn-p

import * as typeorm from 'typeorm';
.
.
.
    jest.spyOn(typeorm, 'getRepository').mockImplementation(() => 
      const original = jest.requireActual('typeorm');
      // You need all functions used in your Query builder
      return 
        ...original,
        createQueryBuilder: jest.fn().mockImplementation(() => (
          subQuery: jest.fn().mockReturnThis() as unknown,
          from: jest.fn().mockReturnThis() as unknown,
          where: jest.fn().mockReturnThis() as unknown,
          select: jest.fn().mockReturnThis() as unknown,
          getQuery: jest.fn().mockReturnThis() as unknown,
          setParameter: jest.fn().mockReturnThis() as unknown,
          getMany: jest.fn().mockResolvedValue(expected) as unknown,
        )),
      ;
    );

【讨论】：

我也有同样的问题=(你找到解决办法了吗？