Validators should at model level and not at AR:Base level [Closes #4804]

[#4804 state:resolved]
Signed-off-by: NDavid Heinemeier Hansson <david@loudthinking.com>

activemodel/lib/active_model/validations.rb

@@ -54,7 +54,7 @@ module Validations
 
       attr_accessor :validation_context
 
-      class_attribute :_validators
+      class_inheritable_accessor :_validators
       self._validators = Hash.new { |h,k| h[k] = [] }
     end
 

activerecord/test/cases/validations_test.rb

@@ -9,6 +9,8 @@
 require 'models/owner'
 require 'models/pet'
 require 'models/event'
+require 'models/parrot'
+require 'models/company'
 
 class ProtectedPerson < ActiveRecord::Base
   set_table_name 'people'
@@ -189,4 +191,12 @@ def test_validate_is_deprecated_on_update
     end
     assert_equal ["always invalid", "invalid on update"], p.errors[:name]
   end
+
+  def test_validators
+    assert_equal 1, Parrot.validators.size
+    assert_equal 1, Company.validators.size
+    assert_equal 1, Parrot.validators_on(:name).size
+    assert_equal 1, Company.validators_on(:name).size
+  end
+
 end