Ruby优化继承类实例

class SubjectMatterExpert < User 
 include HashCodeCreatorModule 
 def make_activation_code 
   self.deleted_at = nil 
   self.activation_code ||= make_hash_code 
 end 
end 
 
class Administrator < User 
 include HashCodeCreatorModule 
 def make_activation_code 
   self.deleted_at = nil 
   self.activation_code ||= make_hash_code 
 end 
end 

class SubjectMatterExpert < User 
end 
 
class Administrator < User 
end 
 
class User 
 include HashCodeCreatorModule 
 def make_activation_code 
   self.deleted_at = nil 
   self.activation_code ||= make_hash_code 
 end 

it 'should create an activation code' do 
  admin = Factory(:administrator) 
  admin.make_activation_code 
  admin.activation_code.should_not be_empty 
end