Jasmine and babel rewire spy on a referenced method

Question

How can I spy on a function that is being called from a reference to it inside an object ? I use Jasmine 2.5.2 as my testing framework and babel-plugin-rewire to rewire dependencies.

Take a look:

a.js

const map = {
 a,
 b,
 c
};
function run(options)  {
 map[options.val]();
}
function a() {...}
function b() {...}
function c() {...}

a.spec.js

import { a, __RewireAPI__ as ARewireAPI } from './a';

describe('a', () => {
  describe('run', () => {
    const spy= jasmine.createSpy('spy').and.callFake(() => {
      ...
    });
    beforeEach(() => {
      ARewireAPI.__Rewire__('b', spy);
    });
    afterEach(() => {
      ARewireAPI.__ResetDependency__('b');
    });
    it('calls b()', () => {
      a.run({val: 'b'}); // doesn't call the spy because what actually being called is the reference from the map object
    });
  });
});

Answer 1

Ok found a solution. Instead of rewiring the function rewire the map like so:

beforeEach(() => {
      ARewireAPI.__Rewire__('map', {b: spy});
    });
    afterEach(() => {
      ARewireAPI.__ResetDependency__('map');
    });