Mockingoose

A Jest package for mocking mongoose models

Installation

$ npm i mockingoose -D

Import the library

// using commonJS
const mockingoose = require('mockingoose').default;

// using es201x
import mockingoose from 'mockingoose';

Usage

// user.js
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);

mockingoose(Model).toReturn(obj, operation = 'find')

Returns a plain object.

// __tests__/user.test.js
import mockingoose from 'mockingoose';

import model from './user';

describe('test mongoose User model', () => {
  it('should return the doc with findById', () => {
    const _doc = {
      _id: '507f191e810c19729de860ea',
      name: 'name',
      email: 'name@email.com',
    };

    mockingoose(model).toReturn(_doc, 'findOne');

    return model.findById({ _id: '507f191e810c19729de860ea' }).then(doc => {
      expect(JSON.parse(JSON.stringify(doc))).toMatchObject(_doc);
    });
  });

  it('should return the doc with update', () => {
    const _doc = {
      _id: '507f191e810c19729de860ea',
      name: 'name',
      email: 'name@email.com',
    };

    mockingoose(model).toReturn(doc, 'update');

    return model
      .update({ name: 'changed' }) // this won't really change anything
      .where({ _id: '507f191e810c19729de860ea' })
      .then(doc => {
        expect(JSON.parse(JSON.stringify(doc))).toMatchObject(_doc);
      });
  });
});

mockingoose(Model).toReturn(fn, operation = 'find')

Allows passing a function in order to return the result.

You will be able to inspect the query using the parameter passed to the function. This will be either a Mongoose Query or Aggregate class, depending on your usage.

You can use snapshots to automatically test that the queries sent out are valid.

// __tests__/user.test.js
import mockingoose from 'mockingoose';
import model from './user';

describe('test mongoose User model', () => {
  it('should return the doc with findById', () => {
    const _doc = {
      _id: '507f191e810c19729de860ea',
      name: 'name',
      email: 'name@email.com',
    };
    const finderMock = query => {
      expect(query.getQuery()).toMatchSnapshot('findById query');

      if (query.getQuery()._id === '507f191e810c19729de860ea') {
        return _doc;
      }
    };

    mockingoose(model).toReturn(finderMock, 'findOne'); // findById is findOne

    return model.findById('507f191e810c19729de860ea').then(doc => {
      expect(JSON.parse(JSON.stringify(doc))).toMatchObject(_doc);
    });
  });
});

mockingoose(Model).reset(operation = undefined)

will reset Model mock, if pass an operation, will reset only this operation mock.

it('should reset model mock', () => {
  mockingoose(model).toReturn({ name: '1' });
  mockingoose(model).toReturn({ name: '2' }, 'save');

  mockingoose(model).reset(); // will reset all operations;
  mockingoose(model).reset('find'); // will reset only find operations;
});

you can also chain mockingoose#ModelName operations:

mockingoose(model)
  .toReturn({ name: 'name' })
  .toReturn({ name: 'a name too' }, 'findOne')
  .toReturn({ name: 'another name' }, 'save')
  .reset('find');

mockingoose.resetAll()

will reset all mocks.

beforeEach(() => {
  mockingoose.resetAll();
});

Operations available:

Notes

The library is built with Typescript and typings are included.

All operations work with exec, promise and callback.

if you are using Model.create and you don't pass a mock with mockingoose you'll receive the mongoose created doc (with ObjectId and transformations)
validations are working as expected.
the returned document is an instance of mongoose Model.
update operation returns original mocked object.

you can simulate Error by passing an Error to mockingoose:

mockingoose(model).toReturn(new Error('My Error'), 'save');

return model.create({ name: 'name', email: 'name@email.com' }).catch(err => {
  expect(err.message).toBe('My Error');
});

you can mock .populate in your mocked result just be sure to change the Schema's path to appropriate type (eg: Object | Mixed):

User.schema.path('foreignKey', Object);

const doc = {
  email: 'test@mail.com',
  foreignKey: {
    _id: '5ca4af76384306089c1c30ba',
    name: 'test',
    value: 'test',
  },
  name: 'Name',
  saveCount: 1,
};
  
mockingoose(User).toReturn(doc);
  
const result = await User.find();
  
expect(result).toMatchObject(doc);

no connection is made to the database (mongoose.connect is jest.fn())
will work with node 6.4.x. tested with mongoose 4.x and jest 20.x.
check tests for more, feel free to fork and contribute.

Recent Changes:

mockingoose.ModelName is deprecated, mockingoose(Model) is the now the recommended usage, with Model being a Mongoose model class.

Alternatively, you may pass a string with the model name.
mockingoose(Model).toReturn((query) => value) can now take also take a function as a parameter.

The function is called with either a Query or Aggregate object from Mongoose, depending on the request. This allows tests to ensure that proper queries are sent out, and helps with regression testing.

ruslan-zhuba / mockingoose