Make ActiveResource serialize XML correctly when element_name is set.

[#4529]
Signed-off-by: NJeremy Kemper <jeremy@bitsweat.net>

activemodel/lib/active_model/serializers/xml.rb

@@ -90,7 +90,7 @@ def serialize
           @builder = options[:builder]
           @builder.instruct! unless options[:skip_instruct]
 
-          root = (options[:root] || @serializable.class.model_name.singular).to_s
+          root = (options[:root] || @serializable.class.model_name.element).to_s
           root = ActiveSupport::XmlMini.rename_key(root, options)
 
           args = [root]

activemodel/test/cases/serializeration/xml_serialization_test.rb

@@ -37,8 +37,8 @@ def setup
 
   test "should serialize namespaced root" do
     @xml = Admin::Contact.new(@contact.attributes).to_xml
-    assert_match %r{^<admin-contact>},  @xml
-    assert_match %r{</admin-contact>$}, @xml
+    assert_match %r{^<contact>},  @xml
+    assert_match %r{</contact>$}, @xml
   end
 
   test "should serialize default root with namespace" do

activeresource/lib/active_resource/base.rb

@@ -551,11 +551,22 @@ def headers
         @headers ||= {}
       end
 
-      # Do not include any modules in the default element name. This makes it easier to seclude ARes objects
-      # in a separate namespace without having to set element_name repeatedly.
-      attr_accessor_with_default(:element_name)    { ActiveSupport::Inflector.underscore(to_s.split("::").last) } #:nodoc:
+      def element_name
+        model_name.element
+      end
+
+      def element_name=(value)
+        model_name.element = value
+      end
+
+      def collection_name
+        model_name.collection
+      end
+
+      def collection_name=(value)
+        model_name.collection = value
+      end
 
-      attr_accessor_with_default(:collection_name) { ActiveSupport::Inflector.pluralize(element_name) } #:nodoc:
       attr_accessor_with_default(:primary_key, 'id') #:nodoc:
 
       # Gets the \prefix for a resource's nested URL (e.g., <tt>prefix/collectionname/1.xml</tt>)

activeresource/test/cases/base_test.rb

@@ -1018,6 +1018,23 @@ def test_to_xml
     assert xml.include?('<id type="integer">1</id>')
   end
 
+  def test_to_xml_with_element_name
+    old_elem_name = Person.element_name
+    matz = Person.find(1)
+    Person.element_name = 'ruby_creator'
+    encode = matz.encode
+    xml = matz.to_xml
+
+    assert encode, xml
+    assert xml.include?('<?xml version="1.0" encoding="UTF-8"?>')
+    assert xml.include?('<ruby-creator>')
+    assert xml.include?('<name>Matz</name>')
+    assert xml.include?('<id type="integer">1</id>')
+    assert xml.include?('</ruby-creator>')
+  ensure
+    Person.element_name = old_elem_name
+  end
+
   def test_to_json
     Person.include_root_in_json = true
     Person.format = :json
@@ -1033,6 +1050,25 @@ def test_to_json
     assert_match %r{\}\}\}$}, json
   end
 
+  def test_to_json_with_element_name
+    old_elem_name = Person.element_name
+    Person.include_root_in_json = true
+    Person.format = :json
+    joe = Person.find(6)
+    Person.element_name = 'ruby_creator'
+    encode = joe.encode
+    json = joe.to_json
+    Person.format = :xml
+
+    assert encode, json
+    assert_match %r{^\{"ruby_creator":\{"person":\{}, json
+    assert_match %r{"id":6}, json
+    assert_match %r{"name":"Joe"}, json
+    assert_match %r{\}\}\}$}, json
+  ensure
+    Person.element_name = old_elem_name
+  end
+
   def test_to_param_quacks_like_active_record
     new_person = Person.new
     assert_nil new_person.to_param