如何使用 Jest 對 typeorm getRepository 進行單元測試？

Question

我將 typescript 與 typeorm 一起使用，並且我有一個這樣的存儲庫：

import { EntityRepository, getRepository, createQueryBuilder } from 'typeorm';


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

我的測試文件是這樣的

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(),
      }));
        ...
    });
  },
);

我如何直接從仍符合 typescript 類型檢查的 typeorm 模擬 getRepository？

Answer 1

我剛剛遇到了這個問題，實際上我使用您的代碼作為我的解決方案的基礎。 請試試這個：

    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,
        })),
      };
    });

Answer 2

在更新 jest 庫后遇到了同樣的問題，通過 mocking getRepository 方法直接從 typeorm/globals 而不是 typeorm(index file) 解決了這個問題

import * as typeorm_functions from 'typeorm/globals';

jest.spyOn(typeorm_functions, 'getRepository').mockReturnValue({
 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,
    })),
} as unknown as Repository<unknown>);

Answer 3

我在使用已批准的解決方案時遇到以下錯誤：

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

為了解決這個問題，我改用了以下導入語句：

import * as typeorm from "typeorm/globals";

Answer 4

當我嘗試這樣做時，出現以下錯誤

 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 {

看我的片段

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,
        })),
      };
    });