Mocking Sequelize model function

user.js

var Promise = require('bluebird');
var sinon = require('sinon');
var User = require('./db/models').User;

describe('User model', function(){
  var userFindStub;
  var sandbox;
  
  before(function(){
    sandbox = sinon.sandbox.create();
    userFindStub = sanbox.stub(User, 'find');
  })
  
  it('should catch', function(){
    userFindStub.returns(Promise.reject(new Error('test-error')))
    return User.find({})
      .catch(function(err){
        should.exist(err);
        err.message.should.equal('test-error');
      })
  })
})