do not let users register on an event that has not been specifically enabled at initialize. add test.

git-svn-id: http://svn.openlayers.org/trunk/openlayers@872 dc9f47b5-9b13-0410-9fdd-eb0c1a62fdaf

lib/OpenLayers/Events.js

@@ -105,8 +105,10 @@ OpenLayers.Events.prototype = {
                 obj = this.object;
             }
             var listeners = this.listeners[type];
+            if (listeners != null) {
                 listeners.push( {obj: obj, func: func} );
             }
+        }
     },
     
     /**

tests/test_Events.html

@@ -41,7 +41,7 @@
 
     function test_02_Events_register_unregister(t) {
  
-        t.plan( 13 );
+        t.plan( 14 );
  
         var mapDiv = $('map');
         var obj = {result: 0};
@@ -78,6 +78,9 @@
         var listenerList = events.listeners["doThingA"];
         t.eq( listenerList.length, 3, "register correctly does not append null callback to event.listeners[doThingA] even when obj passed in is null" );
 
+        events.register( "chicken", obj, func);
+        t.ok( events.listeners["chicken"] == null, "register() does nothing on attempt to register un-enabled event");
+
         events.unregister("doThingA", obj, null);
         var listenerList = events.listeners["doThingA"];
         t.eq( listenerList.length, 3, "trying to unregister a null callback does nothing -- but doesnt crash :-)" );