Sinon Stub With Es6-promisified Object

Ok my setup is as follows: Using node 6.2, es6-promisify, sinon, sinon-as-promised, and babel to transpile support for es6 import/export. My code under test looks something like th

Solution 1:

The problem ultimately has to do with how ES6 import/exports work, and specifically, how they make your code look better but prevent easy spying/stubbing.

Take this example module:

// my-module.js
function someFunction() {
  console.log('original');
};

export let get = someFunction;

export default function() {
  get();
};

A test case for that code could look like this:

import * as sinon from 'sinon';
import * as should from 'should';
import setup, * as myModule from './my-module';

it('should call get()', () => {
  let stub = sinon.stub(myModule, 'get');
  setup();
  stub.called.should.eql(true);
});

You'll see that the original get() gets called, and not the stub. This is because in the module, get is a local (to the module) reference. Sinon is stubbing another reference to the same function, in the exported object.

To make this work, instead of using a local reference in the module, you need to use the one in the exported object:

export default function() {
  exports.get();
};

Which, alas, makes for uglier code.