Fix default_serializer_options, closes #112 & #113

Allow options such as :serializer, :scope, :root etc to be set via
default_serializer_options and allow the inline options to override such
defaults.

lib/action_controller/serialization.rb

@@ -40,6 +40,8 @@ module ActionController
     end
 
     def _render_option_json(json, options)
+      options = default_serializer_options.merge(options) if default_serializer_options
+
       serializer = options.delete(:serializer) ||
         (json.respond_to?(:active_model_serializer) && json.active_model_serializer)
 
@@ -59,7 +61,7 @@ module ActionController
       if serializer
         options[:scope] = serialization_scope unless options.has_key?(:scope)
         options[:url_options] = url_options
-        json = serializer.new(json, options.merge(default_serializer_options || {}))
+        json = serializer.new(json, options)
       end
       super
     end

test/serialization_test.rb

@@ -54,6 +54,15 @@ class RenderJsonTest < ActionController::TestCase
     end
   end
 
+  class AnotherCustomSerializer
+    def initialize(*)
+    end
+
+    def as_json(*)
+      { :rails => 'rocks' }
+    end
+  end
+
   class HypermediaSerializable
     def active_model_serializer
       HypermediaSerializer
@@ -175,9 +184,13 @@ class RenderJsonTest < ActionController::TestCase
 
   private
     def default_serializer_options
-      if params[:check_defaults]
-        { :check_defaults => true }
-      end
+      defaults = {}
+      defaults.merge!(:check_defaults => true) if params[:check_defaults]
+      defaults.merge!(:root => :awesome) if params[:check_default_root]
+      defaults.merge!(:scope => :current_admin) if params[:check_default_scope]
+      defaults.merge!(:serializer => AnotherCustomSerializer) if params[:check_default_serializer]
+      defaults.merge!(:each_serializer => AnotherCustomSerializer) if params[:check_default_each_serializer]
+      defaults
     end
   end
 
@@ -258,11 +271,26 @@ class RenderJsonTest < ActionController::TestCase
     assert_match '"check_defaults":true', @response.body
   end
 
+  def test_render_json_with_serializer_checking_default_serailizer
+    get :render_json_with_serializer, :check_default_serializer => true
+    assert_match '{"rails":"rocks"}', @response.body
+  end
+
+  def test_render_json_with_serializer_checking_default_scope
+    get :render_json_with_serializer, :check_default_scope => true
+    assert_match '"scope":"current_admin"', @response.body
+  end
+
   def test_render_json_with_serializer_and_implicit_root
     get :render_json_with_serializer_and_implicit_root
     assert_match '"test":[{"serializable_object":true}]', @response.body
   end
 
+  def test_render_json_with_serializer_and_implicit_root_checking_default_each_serailizer
+    get :render_json_with_serializer_and_implicit_root, :check_default_each_serializer => true
+    assert_match '"test":[{"rails":"rocks"}]', @response.body
+  end
+
   def test_render_json_with_serializer_and_options
     get :render_json_with_serializer_and_options
     assert_match '"scope":{"current_user":true}', @response.body
@@ -275,6 +303,11 @@ class RenderJsonTest < ActionController::TestCase
     assert_match '"scope":{"current_user":false}', @response.body
   end
 
+  def test_render_json_with_serializer_and_scope_option_checking_default_scope
+    get :render_json_with_serializer_and_scope_option, :check_default_scope => true
+    assert_match '"scope":{"current_user":false}', @response.body
+  end
+
   def test_render_json_with_serializer_api_but_without_serializer
     get :render_json_with_serializer_api_but_without_serializer
     assert_match '{"serializable_object":true}', @response.body
@@ -285,6 +318,11 @@ class RenderJsonTest < ActionController::TestCase
     assert_match '{"hello":true}', @response.body
   end
 
+  def test_render_json_with_custom_serializer_checking_default_serailizer
+    get :render_json_with_custom_serializer, :check_default_serializer => true
+    assert_match '{"hello":true}', @response.body
+  end
+
   def test_render_json_array_with_custom_serializer
     get :render_json_array_with_custom_serializer
     assert_match '{"test":[{"hello":true}]}', @response.body
@@ -296,6 +334,11 @@ class RenderJsonTest < ActionController::TestCase
     end
   end
 
+  def test_render_json_array_with_custom_serializer_checking_default_each_serailizer
+    get :render_json_array_with_custom_serializer, :check_default_each_serializer => true
+    assert_match '{"test":[{"hello":true}]}', @response.body
+  end
+
   def test_render_json_with_links
     get :render_json_with_links
     assert_match '{"link":"http://www.nextangle.com/hypermedia"}', @response.body
@@ -306,11 +349,21 @@ class RenderJsonTest < ActionController::TestCase
     assert_equal '[]', @response.body
   end
 
+  def test_render_json_array_with_no_root_checking_default_root
+    get :render_json_array_with_no_root, :check_default_root => true
+    assert_equal '[]', @response.body
+  end
+
   def test_render_json_empty_array
     get :render_json_empty_array
     assert_equal '{"test":[]}', @response.body
   end
 
+  def test_render_json_empty_array_checking_default_root
+    get :render_json_empty_array, :check_default_root => true
+    assert_equal '{"awesome":[]}', @response.body
+  end
+
   def test_render_json_empty_arry_with_array_serializer_root_false
     ActiveModel::ArraySerializer.root = false
     get :render_json_empty_array