gistfile1.rbx

class Grandparent
end

class Parent < Grandparent
end

class Child < Parent
end

class Grandparent
  class_inheritable_accessor :last_name, :_attribute

  self._attribute = "1900"  
end

describe Class, "#inheritable_accessor" do
  
  after :each do
    Grandparent.send(:remove_instance_variable, "@last_name") rescue nil
    Parent.send(:remove_instance_variable, "@last_name") rescue nil
    Child.send(:remove_instance_variable, "@last_name") rescue nil
  end

  it 'inherits unless overriden' do
    Parent._attribute.should == "1900"
  end