Create a document in beforeEach on Jest nest.js - testing

Question

I'm Using the in memory mongoose database for create my Unit test, and I want to create a document before the tests.
My interface is:
export interface IUsers {
readonly name: string;
readonly username: string;
readonly email: string;
readonly password: string;
}
and my beforeEach is:
import { MongooseModule } from "#nestjs/mongoose";
import { Test, TestingModule } from "#nestjs/testing";
import { closeInMongodConnection, rootMongooseTestModule } from '../test-utils/mongo/MongooseTestModule';
import { User, UserSchema } from "./schemas/users.schema";
import { UsersService } from "./users.service";
describe("UsersService", () => {
let service: UsersService;
let testingModule: TestingModule;
let userModel: Model<User>;
beforeEach(async () => {
const module: TestingModule = await Test.createTestingModule({
imports: [
rootMongooseTestModule(),
MongooseModule.forFeature([{ name: User.name, schema: UserSchema }]),
],
providers: [UsersService],
}).compile();
service = module.get<UsersService>(UsersService);
//create user
userModel = testingModule.get<Model<User>>(
'UserModel',
);
});
I get an error TypeError: Cannot read pro perties of undefined (reading 'get') during the test. I tried to use let userModel: Model<IUsers>; But I get the same error.

Answer 1

Use either testingModule or module.
You declared testingModule but never initialized.
let testingModule: TestingModule; This part is undefined unless something is assigned to it.
Try like this
describe('UsersService', () => {
let testingModule: TestingModule;
let userModel: Model<User>;
let userService: UserService;
beforeEach(async () => {
testingModule = await Test.createTestingModule({
imports: [
rootMongooseTestModule,
MongooseModule.forFeature([{ name: User.name, schema: UserSchema }])],
providers: [UsersService],
}).compile();
userService = testingModule.get<UsersService>(UsersService);
userModel = testingModule.get<Model<User>>('UserModel');
// await userModel.create(...) or whatever methods you have
});
});