Fix the the backport of the object dup with the ruby 1.9.3p194.

At the end of initialize_dup was added the call to super if it exists,
so it also works with 1.8.7 where initialize_dup doesn't exist.
This issu was introduced with the pull request #6324

2 files changed, 14 insertions, 0 deletions

diff --git a/activemodel/test/cases/validations_test.rb b/activemodel/test/cases/validations_test.rb
index 56c9a5592c..d000a88ce1 100644
--- a/activemodel/test/cases/validations_test.rb
+++ b/activemodel/test/cases/validations_test.rb
@@ -5,6 +5,7 @@ require 'models/topic'
 require 'models/reply'
 require 'models/custom_reader'
 require 'models/automobile'
+require 'models/book'
 
 require 'active_support/json'
 require 'active_support/xml_mini'
@@ -354,4 +355,14 @@ class ValidationsTest < ActiveModel::TestCase
     assert topic.invalid?
     assert duped.valid?
   end
+
+  def test_dup_call_parent_dup_when_include_validations
+    book = Book.new
+    book['title'] = "Litterature"
+    book['author'] = "Foo"
+    duped = book.dup
+
+    assert_equal book.keys, duped.keys
+    assert_equal book.values, duped.values
+  end
 end
diff --git a/activemodel/test/models/book.rb b/activemodel/test/models/book.rb
new file mode 100644
index 0000000000..c5c19046c8
--- /dev/null
+++ b/activemodel/test/models/book.rb
@@ -0,0 +1,3 @@
+class Book < Hash
+  include ActiveModel::Validations
+end