Mock objection model dependecy in NestJs with Jest - unit-testing

Question

I'm trying to make unit test with nestjs and objection. The problem I have is that I can't mock the "User" Model that is injected with the decorator "#InjectModel". I searched a lot to find a solution but I didn't find anything.
users.service.ts
import { HttpException, HttpStatus, Inject, Injectable } from '#nestjs/common';
import { CreateUserDto } from './create-user.dto';
import { User } from 'src/app.models';
import { InjectModel } from 'nestjs-objection';
#Injectable()
export class UsersService {
constructor(
#InjectModel(User) private readonly userModel: typeof User,
) {}
async create(createUserDto: CreateUserDto) {
try {
const users = await this.userModel.query().insert(createUserDto);
return users
} catch (err) {
console.log(err)
throw new HttpException(err, HttpStatus.BAD_REQUEST);
}
}
}
users.service.spec.ts
import { Test, TestingModule } from "#nestjs/testing";
import { UsersService } from "../src/users/users.service";
import { CreateUserDto } from "src/users/create-user.dto";
import { User } from "../src/app.models";
import { getObjectionModelToken } from 'nestjs-objection';
describe('userService', () => {
let userService: UsersService;
beforeEach(async () => {
const module: TestingModule = await Test.createTestingModule({
providers: [
UsersService,
{
provide: User,
useValue: {}
},
],
}).compile();
userService = module.get<UsersService>(UsersService);
});
it('Should be defined', () => {
expect(userService).toBeDefined();
});
it('Should add pin to a created user', async () => {
const createUserDTO: CreateUserDto = {
email: 'mockEmail#mock.com',
userName: 'user'
}
const res = await userService.create(createUserDTO)
expect(res).toHaveProperty('pin')
});
I tried to use import { getObjectionModelToken } from 'nestjs-objection'; inside provider like this:
providers: [
UsersService,
{
provide: getObjectionModelToken(User),
useValue: {}
},
],
I got this error
It asks for a "connection" but I don't know what to put on it.
I suppose "getObjectionModelToken" is the function to mock the "InjectModel". When I pass an empty string
I got this error:
● Test suite failed to run
Cannot find module 'src/app.models' from '../src/users/users.service.ts'
Require stack:
C:/nestjs-project/nestjs-knex/src/users/users.service.ts
users.repository.spec.ts
1 | import { HttpException, HttpStatus, Inject, Injectable } from '#nestjs/common';
2 | import { CreateUserDto } from './create-user.dto';
> 3 | import { User } from 'src/app.models';
| ^
4 | import {
5 | InjectModel,
6 | synchronize,
at Resolver._throwModNotFoundError (../node_modules/jest-resolve/build/resolver.js:491:11)
at Object.<anonymous> (../src/users/users.service.ts:3:1)
If I change the path it breaks the correct functionality of the app

Answer 1

That looks like an error from jest not understanding what src/* imports are. Either use relative imports rather than absolute (e.g. use import { User } from '../app.models') or tell jest how to resolve src/* imports via the moduleNameMapper in your jest.config.js or package.json
{
"moduleNameMapper": {
"^src/(.*)$": "<rootDir>/path/to/src/$1"
}
}
I think based on the error your /path/to/src should be ../src but I'm not 100% sure, so make sure you set that correctly.