When using this neat snippet from Dr Nic for testing a plugin I use internally, I came across the behavior described by Avdi. The proposed solution works great!
A single line modification to Dr Nic’s class ensures it works with class_inheritable_accessor from ActiveSupport.
def create_class(class_name, superclass, &block) klass = Class.new superclass klass.instance_eval &block Object.const_set class_name, klass end