Support serializer and each_serializer in render json

test/action_controller/explicit_serializer_test.rb

@@ -0,0 +1,53 @@
+require 'test_helper'
+
+module ActionController
+  module Serialization
+    class ExplicitSerializerTest < ActionController::TestCase
+      class MyController < ActionController::Base
+        def render_using_explicit_serializer
+          @profile = Profile.new(name: 'Name 1',
+                                 description: 'Description 1',
+                                 comments: 'Comments 1')
+          render json: @profile, serializer: ProfilePreviewSerializer
+        end
+
+        def render_array_using_explicit_serializer
+          array = [
+            Profile.new(name: 'Name 1',
+                        description: 'Description 1',
+                        comments: 'Comments 1'),
+            Profile.new(name: 'Name 2',
+                        description: 'Description 2',
+                        comments: 'Comments 2')
+          ]
+          render json: array,
+                 serializer: PaginatedSerializer,
+                 each_serializer: ProfilePreviewSerializer
+        end
+      end
+
+      tests MyController
+
+      def test_render_using_explicit_serializer
+        get :render_using_explicit_serializer
+
+        assert_equal 'application/json', @response.content_type
+        assert_equal '{"name":"Name 1"}', @response.body
+      end
+
+      def test_render_array_using_explicit_serializer
+        get :render_array_using_explicit_serializer
+        assert_equal 'application/json', @response.content_type
+
+        expected = {
+          'paginated' => [
+            { 'name' => 'Name 1' },
+            { 'name' => 'Name 2' }
+          ]
+        }
+
+        assert_equal expected.to_json, @response.body
+      end
+    end
+  end
+end