diff --git a/test/action_controller/serialization_test.rb b/test/action_controller/serialization_test.rb
index 12a75f2d..e84c4b7e 100644
--- a/test/action_controller/serialization_test.rb
+++ b/test/action_controller/serialization_test.rb
@@ -9,20 +9,6 @@ module ActionController
           render json: @profile
         end
 
-        def render_using_custom_root
-          with_adapter ActiveModel::Serializer::Adapter::Json do
-            @profile = Profile.new({ name: 'Name 1', description: 'Description 1', comments: 'Comments 1' })
-            render json: @profile, root: "custom_root"
-          end
-        end
-
-        def render_using_custom_root_and_meta
-          with_adapter ActiveModel::Serializer::Adapter::Json do
-            @profile = Profile.new({ name: 'Name 1', description: 'Description 1', comments: 'Comments 1' })
-            render json: @profile, root: "custom_root", meta: { total: 10 }
-          end
-        end
-
         def render_using_default_adapter_root
           with_adapter ActiveModel::Serializer::Adapter::JsonApi do
             # JSON-API adapter sets root by default
@@ -31,22 +17,6 @@ module ActionController
           end
         end
 
-        def render_using_custom_root_in_adapter_with_a_default
-          # JSON-API adapter sets root by default
-          @profile = Profile.new({ name: 'Name 1', description: 'Description 1', comments: 'Comments 1' })
-          render json: @profile, root: "profile", adapter: :json_api
-        end
-
-        def render_array_using_custom_root_and_meta
-          with_adapter ActiveModel::Serializer::Adapter::Json do
-            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, root: "custom_root", meta: { total: 10 }
-          end
-        end
-
         def render_array_using_implicit_serializer
           array = [
             Profile.new({ name: 'Name 1', description: 'Description 1', comments: 'Comments 1' }),
@@ -191,24 +161,6 @@ module ActionController
         assert_equal expected.to_json, @response.body
       end
 
-      def test_render_using_custom_root_in_adapter_with_a_default
-        get :render_using_custom_root_in_adapter_with_a_default
-
-        expected = {
-          data: {
-            id: assigns(:profile).id.to_s,
-            type: "profiles",
-            attributes: {
-              name: "Name 1",
-              description: "Description 1"
-            }
-          }
-        }
-
-        assert_equal 'application/json', @response.content_type
-        assert_equal expected.to_json, @response.body
-      end
-
       def test_render_array_using_implicit_serializer
         get :render_array_using_implicit_serializer
         assert_equal 'application/json', @response.content_type
diff --git a/test/serializers/meta_test.rb b/test/serializers/meta_test.rb
index 802049eb..7b613ab3 100644
--- a/test/serializers/meta_test.rb
+++ b/test/serializers/meta_test.rb
@@ -13,7 +13,7 @@ module ActiveModel
 
       def test_meta_is_present_with_root
         serializer = AlternateBlogSerializer.new(@blog, meta: {total: 10})
-        adapter = ActiveModel::Serializer::Adapter::Json.new(serializer, root: 'blog')
+        adapter = ActiveModel::Serializer::Adapter::Json.new(serializer)
         expected = {
           alternate_blog: {
             id: 1,
@@ -27,6 +27,7 @@ module ActiveModel
       end
 
       def test_meta_is_not_included_when_root_is_missing
+        # load_adapter uses FlattenJson Adapter
         adapter = load_adapter(meta: {total: 10})
         expected = {
           id: 1,
@@ -36,7 +37,7 @@ module ActiveModel
       end
 
       def test_meta_key_is_used
-        serializer = AlternateBlogSerializer.new(@blog, root: 'blog', meta: {total: 10}, meta_key: "haha_meta")
+        serializer = AlternateBlogSerializer.new(@blog, meta: {total: 10}, meta_key: "haha_meta")
         adapter = ActiveModel::Serializer::Adapter::Json.new(serializer, root: 'blog')
         expected = {
           alternate_blog: {
@@ -52,6 +53,7 @@ module ActiveModel
 
       def test_meta_is_not_present_on_arrays_without_root
         serializer = ArraySerializer.new([@blog], meta: {total: 10})
+        # FlattenJSON doesn't have support to root
         adapter = ActiveModel::Serializer::Adapter::FlattenJson.new(serializer)
         expected = [{
           id: 1,
@@ -71,7 +73,8 @@ module ActiveModel
 
       def test_meta_is_present_on_arrays_with_root
         serializer = ArraySerializer.new([@blog], meta: {total: 10}, meta_key: "haha_meta")
-        adapter = ActiveModel::Serializer::Adapter::Json.new(serializer, root: 'blog')
+        # JSON adapter adds root by default
+        adapter = ActiveModel::Serializer::Adapter::Json.new(serializer)
         expected = {
           blogs: [{
             id: 1,