Unit tests in NestJS

Hello I have following setup for unit test:

import { Test, TestingModule } from '@nestjs/testing';
import { BlockchainService } from '../blockchain/blockchain.service';
import { FaucetService } from '../faucet/faucet.service';
import { UserController } from './user.controller';
import { UserService } from './user.service';

describe('UserController', () => {
    let controller: UserController;
    let userService: UserService;
    let faucetService: FaucetService;
    let blockchainService: BlockchainService;

    beforeEach(async () => {
        const module: TestingModule = await Test.createTestingModule({
            controllers: [UserController],
            providers: [UserService, FaucetService, BlockchainService],
        }).compile();

        controller = module.get<UserController>(UserController);
        userService = module.get<UserService>(UserService);
        faucetService = module.get<FaucetService>(FaucetService);
        blockchainService = module.get<BlockchainService>(BlockchainService);
    });

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

Issue is that when I run the tests this is the response:

Cannot find module 'src/config/app.config' from 'modules/user/user.service.ts'

AppConfig is util object which contains env.variables, my question is how to import/mock this object and other utils functions so my test could compile successfully.

Thanks in advance!