jquery data: closes #5224. Exposing the expando.

src/data.js

@@ -2,6 +2,8 @@ var expando = "jQuery" + now(), uuid = 0, windowData = {};
 
 jQuery.extend({
 	cache: {},
+
+	expando:expando,
 
 	data: function( elem, name, data ) {
 		elem = elem == window ?

test/unit/data.js

@@ -1,5 +1,21 @@
 module("data");
 
+test("expando", function(){
+	expect(4);
+
+	equals("expando" in jQuery, true, "jQuery is exposing the expando");
+
+	var obj = {};
+	jQuery.data(obj, "foo", "bar");
+
+	equals(jQuery.expando in obj, true, "jQuery.data added an expando to the object");	
+
+	var id = obj[jQuery.expando];
+	equals( id in jQuery.cache, true, "jQuery.data added an entry to jQuery.cache");
+
+	equals( jQuery.cache[id].foo, "bar", "jQuery.data worked correctly");
+});
+
 test("jQuery.data", function() {
 	expect(5);
 	var div = jQuery("#foo")[0];