How to unit test typeorm getRepository with Jest?

Question

I am using typescript with typeorm and i have an repository like this:

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


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

my test file is like this

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

how do i mock getRepository directly from typeorm which is still complying to typescript type check?

Answer 1

I just had this issue, I actually used your code as a base for my solution. Please try this:

    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,
        })),
      };
    });