Added test todo for class_builder

lib/class_builder.js

@@ -20,6 +20,11 @@
  *
  * @author  Mike Gerwitz
  * @package core
+ *
+ * TODO: This module is currently being tested /indirectly/ by the class tests.
+ *       This is because of a refactoring. All of this logic used to be part of
+ *       the class module. Test this module directly, but keep the existing
+ *       class tests in tact for a higher-level test.
  */
 
 var util           = require( __dirname + '/util' ),