prototype: Ensure that classes always have an initialize method.

CHANGELOG

@@ -1,5 +1,7 @@
 *SVN*
 
+* Ensure that classes always have an initialize method.  [Mislav Marohnić]
+
 * Update Template, Selector, Ajax.*, and ObjectRange classes to use the new class system.  [Mislav Marohnić]
 
 * Change Abstract.TimedObserver to subclass PeriodicalExecuter and tweak its subclasses to use new inheritance functionality.  TimedObserver can now be stopped the same way as PeriodicalExecuter.  Closes #8589.  [Mislav Marohnić]

src/base.js

@@ -21,6 +21,9 @@ var Class = {
       }
 
       if (properties) Class.extend(klass, properties);
+      if (!klass.prototype.initialize)
+        klass.prototype.initialize = Prototype.emptyFunction;
+        
       klass.prototype.constructor = klass;
 
       return klass;

test/unit/base.html

@@ -415,6 +415,9 @@
       assertEqual('Nibbles: Hi!', pet.say('Hi!'));
       assertEqual(Animal, pet.constructor, "bad constructor reference");
       assertUndefined(pet.superclass);
+
+      var Empty = Class.create();
+      assert('object', typeof new Empty);
     }},
 
     testInheritance: function() { with(this) {