I'd like to unit test the following ES6 class:

// service.js

const InternalService = require('internal-service');



class Service {

  constructor(args) {

    this.internalService = new InternalService(args);

  }



  getData(args) {   

    let events = this.internalService.getEvents(args);

    let data = getDataFromEvents(events);

    return data;

  }

}



function getDataFromEvents(events) {...}



module.exports = Service;

How do I mock constructor with Sinon.JS in order to mock getEvents of internalService to test getData?

I looked at Javascript: Mocking Constructor using Sinon but wasn't able to extract a solution.

// test.js

const chai = require('chai');

const sinon = require('sinon');

const should = chai.should();



let Service = require('service');



describe('Service', function() {

  it('getData', function() {

    // throws: TypeError: Attempted to wrap undefined property Service as function

    sinon.stub(Service, 'Service').returns(0);

  });

});