Sinon Mongoose mock example

gistfile1.txt

import * as sinon from 'sinon';
import * as Mongoose from 'mongoose';
import { expect } from 'chai';

// test utility
function areObjectIdsEqual(id1: Mongoose.Types.ObjectId | string, id2: Mongoose.Types.ObjectId | string) {
  let normalizedId1: Mongoose.Types.ObjectId = new Mongoose.Types.ObjectId(id1.toString());
  let normalizedId2: Mongoose.Types.ObjectId = new Mongoose.Types.ObjectId(id2.toString());
  return normalizedId1.equals(normalizedId2);
}

// test utility
function matchGivenFields(expected) {
  return function(actual) {
    let result: boolean = true;
    for (let key of Object.keys(expected)) {
      if (expected[key] instanceof Mongoose.Types.ObjectId || actual[key] instanceof Mongoose.Types.ObjectId || key === '_id') {
        if (!areObjectIdsEqual(expected[key], actual[key])) {
          console.error('Mismatching ids on: ', key, ', expected: ', expected[key], 'actual: ', actual[key]);
          result = false;
        }
      } else {
        if ((actual[key] !== expected[key])) {
          console.error('Mismatching on: ', key, ', expected: ', expected[key], 'actual: ', actual[key]);
          result = false;
        }
      }
    }
    if (!result) {
      console.log(actual);
    }
    return result;
  };
}

function createUser() {
  let user = new User({name: 'John'});
  return user.save();
}

function findUser(name) {
  return User.findOne({name});
}

describe('simple Mongoose persistence testing', () => {

  let insertStub: sinon.SinonStub;

  let userFindStub: sinon.SinonStub;
  beforeEach(() => {
    insertStub = sinon.stub(Mongoose.Collection.prototype, 'insert', function(docs, options, callback) {
      // console.log('docs', docs);
      callback(null, docs);
    });

    userFindStub = sinon.stub(Client, 'findOne');

    userFindStub.withArgs(sinon.match(matchGivenFields({name: 'John'}))).returns(Promise.resolve(new User({name: 'John'})));
    userFindStub.withArgs({name: 'Alex'}).returns(Promise.resolve(null));
    userFindStub.withArgs(sinon.match.any).returns(Promise.resolve(null));

  });

  afterEach(() => {
    insertStub.restore();
    userFindStub.restore();
  });

  it('should detect that mongoose model was saved', done => {

    createUser.then(() => {
      expect(insertStub.calledOnce).to.be.true;
      expect(insertStub.calledWith(sinon.match(matchGivenFields({
        name: 'John'
      })))).to.be.true;
      done();
    })

  });

  it('should find user John', done => {
    findUser('John').then(() => {
      expect(userFindStub.calledOnce).to.be.true;
      expect(userFindStub.calledWith(sinon.match(matchGivenFields({
        name: 'John'
      })))).to.be.true;
      done();
    })
  });

  it('should not find user John', done => {
    findUser('John').then((user) => {
      expect(user).to.be.null;
      expect(userFindStub.calledOnce).to.be.true;
      expect(userFindStub.calledWith(sinon.match(matchGivenFields({
        name: 'Alex'
      })))).to.be.true;
      done();
    })
  });
});