Screwy way to stub instantiation of a class in js

placer_of_need_spec.js

describe("PlacerOfNeed", function() {
  var placer;
  beforeEach(function() {
    placer = new ForChange.PlacerOfNeed();
  });
  describe("Creating the marker", function() { 
    beforeEach(function()  {
      spyOn(google.maps, 'Marker')
    });
    it("Creates a google marker with the LatLng it created", function() {
      google.maps.LatLng.prototype = { woah: 'man!' }
      placer.place({need: {latitude: 25, longitude: 25}});
      expect(google.maps.Marker).toHaveBeenCalledWith({position: { woah : "man!" }, map: undefined});
      google.maps.LatLng.prototype = {}
    });
  });
});

var ForChange = {};
ForChange.PlacerOfNeed = function() {};
ForChange.PlacerOfNeed.prototype = {
  place: function(options) {
    var coordinates = new google.maps.LatLng(options.need.latitude, options.need.longitude);
    new google.maps.Marker({position: coordinates , map: options.map});

  }

}