Allow overriding the adapter with render option

Make it easy to use multiple adapters in an app.

use "adapter: false" to not use ams

make a test override config.adapter

test/action_controller/adapter_selector_test.rb

@@ -0,0 +1,41 @@
+require 'test_helper'
+
+module ActionController
+  module Serialization
+    class AdapterSelectorTest < ActionController::TestCase
+      class MyController < ActionController::Base
+        def render_using_default_adapter
+          @profile = Profile.new({ name: 'Name 1', description: 'Description 1', comments: 'Comments 1' })
+          render json: @profile
+        end
+
+        def render_using_adapter_override
+          @profile = Profile.new({ name: 'Name 1', description: 'Description 1', comments: 'Comments 1' })
+          render json: @profile, adapter: :json_api
+        end
+
+        def render_skipping_adapter
+          @profile = Profile.new({ name: 'Name 1', description: 'Description 1', comments: 'Comments 1' })
+          render json: @profile, adapter: false
+        end
+      end
+
+      tests MyController
+
+      def test_render_using_default_adapter
+        get :render_using_default_adapter
+        assert_equal '{"name":"Name 1","description":"Description 1"}', response.body
+      end
+
+      def test_render_using_adapter_override
+        get :render_using_adapter_override
+        assert_equal '{"profiles":{"name":"Name 1","description":"Description 1"}}', response.body
+      end
+
+      def test_render_skipping_adapter
+        get :render_skipping_adapter
+        assert_equal '{"attributes":{"name":"Name 1","description":"Description 1","comments":"Comments 1"}}', response.body
+      end
+    end
+  end
+end

test/action_controller/json_api_linked_test.rb

@@ -28,54 +28,34 @@ module ActionController
           @second_comment.author = nil
         end
 
-        def with_json_api_adapter
-          old_adapter = ActiveModel::Serializer.config.adapter
-          ActiveModel::Serializer.config.adapter = :json_api
-          yield
-        ensure
-          ActiveModel::Serializer.config.adapter = old_adapter
-        end
-
         def render_resource_without_include
-          with_json_api_adapter do
-            setup_post
-            render json: @post
-          end
+          setup_post
+          render json: @post, adapter: :json_api
         end
 
         def render_resource_with_include
-          with_json_api_adapter do
-            setup_post
-            render json: @post, include: 'author'
-          end
+          setup_post
+          render json: @post, include: 'author', adapter: :json_api
         end
 
         def render_resource_with_nested_include
-          with_json_api_adapter do
-            setup_post
-            render json: @post, include: 'comments.author'
-          end
+          setup_post
+          render json: @post, include: 'comments.author', adapter: :json_api
         end
 
         def render_resource_with_nested_has_many_include
-          with_json_api_adapter do
-            setup_post
-            render json: @post, include: 'author,author.roles'
-          end
+          setup_post
+          render json: @post, include: 'author,author.roles', adapter: :json_api
         end
 
         def render_collection_without_include
-          with_json_api_adapter do
-            setup_post
-            render json: [@post]
-          end
+          setup_post
+          render json: [@post], adapter: :json_api
         end
 
         def render_collection_with_include
-          with_json_api_adapter do
-            setup_post
-            render json: [@post], include: 'author,comments'
-          end
+          setup_post
+          render json: [@post], include: 'author,comments', adapter: :json_api
         end
       end
 

test/action_controller/serialization_test.rb

@@ -25,13 +25,9 @@ module ActionController
         end
 
         def render_using_custom_root_in_adapter_with_a_default
-          old_adapter = ActiveModel::Serializer.config.adapter
           # JSON-API adapter sets root by default
-          ActiveModel::Serializer.config.adapter = ActiveModel::Serializer::Adapter::JsonApi
           @profile = Profile.new({ name: 'Name 1', description: 'Description 1', comments: 'Comments 1' })
-          render json: @profile, root: "profile"
-        ensure
-          ActiveModel::Serializer.config.adapter = old_adapter
+          render json: @profile, root: "profile", adapter: :json_api
         end
 
         def render_array_using_implicit_serializer