Bacon Jest mocking troubles

example.js

var Bacon = require('baconjs');
var anotherStream = require('./example2');

module.exports = Bacon
  .once("wow")
  // if `anotherStream` is from another JS context,
  // e.g. mocked from jest, this will fail (it shouldn't)
  .merge(anotherStream);

test-example.js

// this example will throw the following error
// example.js: not an EventStream : Bacon.once(yay)
// using my branch from https://github.com/baconjs/bacon.js/pull/639,
// it will work correctly

var Bacon = require('baconjs');

jest.dontMock('../example.js');

describe('stream', function() {
  beforeEach(function(){
    // this will not work, although it's a great feature
    jest.setMock('../example2.js', Bacon.once("yay"));
  });

  pit('streams', function(){
    var stream = require('../example.js');

    return new Promise(function(res, rej){
      stream.slidingWindow(2,2).onValue(function(val){
        expect(val).toEqual(["wow", "yay"]);
        res();
      });
    });
  });
});