factories.js

/*
 * Set up factories, then create them in tests with (for example):
 *
 *   LineItemFactory();
 *
 * Or with attributes / overrides:
 *
 *   LineItemFactory({
 *     "id": 123,
 *     "order": OrderFactory({"firstName": "Example Associated Record Override"}),
 *     "quantity": 4
 *   });
 */
(function(){
	var setUpFactory = function(Type) {
		var defaults = _.toArray(arguments).slice(1);
    
		return function() {
			var obj, objAttributes = [],
				overrides = arguments,
				collection = (defaults.length > overrides.length)? defaults : overrides;
      
			// dynamically gather object defaults and overrides
			for (var i = collection.length - 1; i >= 0; i--) {
				var attributes = _.extend({}, defaults[i], overrides[i]);
				objAttributes.unshift(attributes);
			}
      
			obj = Object.create(Type.prototype);	// set up prototype chain
			Type.apply(obj, objAttributes);			// call constructor on the new object
			return obj;
		};
	};

  //// Factories ////

  window.LineItemFactory = setUpFactory(LineItem, {
    'id': randomId(),
    'order': OrderFactory(),
    'name': 'Some Product Name',
    'price': '14.99',
    'quantity': 1,
    'path': '/products/some-product-name',
    'availability': 'Available now (shipped in 3-5 days)',
    'formatName': 'DVD',
    'imageUrl': 'http://s3.amazonaws.com/myexample/assets/products/123/thumb.jpg?12345',
    'variantOptions': 'Colour: Blue'
  });

  window.OrderFactory = setUpFactory(Order, {
    'id': randomId(),
    'number': 'E12345'
  });


  //// Misc Helpers ////

  function randomId() {
    return Math.floor(Math.random() * 999999) + 1;
  }

})();