Mocking Mongoose model with jest

An other solution is to spyOn the model prototype functions.

For example, this will make MyModel.save() fail :

    jest.spyOn(MyModel.prototype, 'save')      .mockImplementationOnce(() => Promise.reject('fail update'))

You can use mockImplementationOnce to not having to mockRestore the spy. But you can also use mockImplementation and use something like :

afterEach(() => {  jest.restoreAllMocks()})

Tested with "mongoose": "^4.11.7" and "jest": "^23.6.0".

ok, i had the same problem so i author this package to solve this problem:https://www.npmjs.com/package/mockingoose

this is how you can use it let's say this is your model:

import mongoose from 'mongoose';const { Schema } = mongoose;const schema = Schema({    name: String,    email: String,    created: { type: Date, default: Date.now }})export default mongoose.model('User', schema);

and this is your test:

it('should find', () => {  mockingoose.User.toReturn({ name: 2 });  return User  .find()  .where('name')  .in([1])  .then(result => {    expect(result).toEqual({ name: 2 });  })});

checkout the tests folder for more examples:https://github.com/alonronin/mockingoose/blob/master/___tests___/index.test.js

no connections is made to the database!

Mockingoose seems to be a very nice solution. But I was also able to mock my model with Jest.mock() function. At least create method.

// in the module under the test I am creating (saving) DeviceLocation to DB// someBackendModule.js...DeviceLocation.create(location, (err) => {...});...

DeviceLocation model definition:

// DeviceLocation.jsimport mongoose from 'mongoose';const { Schema } = mongoose;const modelName = 'deviceLocation';const DeviceLocation = new Schema({...});export default mongoose.model(modelName, DeviceLocation, modelName);

DeviceLocation mock in the __mocks__ folder in the same folder as DeviceLocation model:

// __mock__/DeviceLocation.jsexport default {    create: (x) => {            return x;    },};

in the test file:

// test.js// calling the mock...jest.mock('../../src/models/mongoose/DeviceLocation');import someBackendModule from 'someBackendModule';...// perform the test