Jest toMatchObject with MongoDB confusing - mongodb

Question

I have a test on my mongoose model and while one models' tests are running completly fine, another one which is basically a copy - does not work. And honestly I don't understand the problem. I tried to remove some of the properties or add hardcoded values to really match 100% exactly - but somehow i always get a similar error.
The error. What drives me crazy is that I tried to remove/add the "_id" and the "createdOn" field but at least the "_id" always appear in the error. As said above in another model the test does not complain about the "_id" because I do not validate it there...I just don't get it.
insert › Should save a channel
expect(received).toMatchObject(expected)
- Expected - 1
+ Received + 2
## -1,8 +1,9 ##
Object {
+ "_id": "5e962f1dc133d8b92891ddaf",
"createdBy": "5e962f1dc133d8b92891ddae",
- "createdOn": Anything,
+ "createdOn": 2020-04-14T21:46:05.907Z,
"hasAcceptedLegal": false,
"isActive": true,
"isPublic": false,
"members": Array [
"5e962f1dc133d8b92891ddae",
48 | expect(spy).toHaveBeenCalled();
49 |
> 50 | expect(channel).toMatchObject({
| ^
51 | name: mockName,
52 | createdBy: mockCreatedById,
53 | createdOn: expect.anything(),
at Object.it (test/model/channel.model.test.ts:50:21)
The respective model
import mongoose, { Schema, Document } from "mongoose";
import { IUser } from "./user.model";
export interface IChannel extends Document {
name: string;
createdBy: IUser["id"];
createdOn: Date;
isActive: boolean;
isPublic: boolean;
hasAcceptedLegal: boolean;
members: [IUser["id"]];
}
const ChannelSchema: Schema = new Schema({
name: { type: String, required: true },
createdBy: {
type: Schema.Types.ObjectId,
ref: "User",
required: true,
},
createdOn: { type: Date },
isActive: { type: Boolean, default: true },
isPublic: { type: Boolean, default: false },
hasAcceptedLegal: { type: Boolean, default: false },
members: [
{
type: Schema.Types.ObjectId,
ref: "User",
required: true,
},
],
});
export default mongoose.model<IChannel>("Channel", ChannelSchema);
The test:
it("Should save a channel", async () => {
expect.assertions(2);
let mockName = Faker.company.companyName();
let mockCreatedById = Types.ObjectId();
let mockCreatedOn = Date.now();
const channel: IChannel = new Channel({
name: mockName,
createdBy: mockCreatedById,
createdOn: mockCreatedOn,
members: [mockCreatedById],
});
const spy = jest.spyOn(channel, "save");
channel.save();
expect(spy).toHaveBeenCalled();
expect(channel).toMatchObject({
name: mockName,
createdBy: mockCreatedById,
createdOn: expect.anything(),
isActive: true,
isPublic: false,
hasAcceptedLegal: false,
members: [mockCreatedById],
});
});

Answer 1

just for reference, I found sth. that the returned mongoose object should be converted with ".toJSON()" and then it works, but even then it was having a problem with the "createdOn" field as it seems to be a formatted Date or sth. like this (no string, parenthesis missing).
What I finally did now was the following and now it works:
it("Should save a channel (required+defaults)", async () => {
expect.assertions(2);
let mockName = Faker.company.companyName();
let mockCreatedById = Types.ObjectId();
let mockCreatedOn = new Date();
const channel: IChannel = new Channel({
name: mockName,
createdBy: mockCreatedById,
createdOn: mockCreatedOn,
members: [mockCreatedById],
});
const spy = jest.spyOn(channel, "save");
channel.save();
expect(spy).toHaveBeenCalled();
expect(channel.toJSON()).toMatchObject({
_id: expect.anything(),
name: mockName,
createdBy: mockCreatedById,
createdOn: expect.anything(),
isActive: true,
isPublic: false,
hasAcceptedLegal: false,
members: expect.arrayContaining([mockCreatedById]),
});
});