Building Enterprise JavaScript Applications

Stubbing create

We can create different stubs that return different results, each mimicking the possible return values of the create function:

import { stub } from 'sinon';import ValidationError from '../../../validators/errors/validation-error';const createStubs = {  success: stub().resolves({ _id: 'foo'}),  validationError: stub().rejects(new ValidationError()),  otherError: stub().rejects(new Error()),}

Now, if we invoke createStubs.success(), it will always resolve to the { _id: 'foo'} object; therefore, we can use this stub to test for scenarios where the req object we pass into the createUser function is valid. Likewise, we can use createStubs.validationError() to mimic a situation where the req object causes createUser to reject with ...