Use serializer name as root when root not set

lib/active_model/serializer.rb

@@ -87,7 +87,7 @@ module ActiveModel
     def root=(root)
       @root = root
       @root = self.class._root if @root.nil?
-      @root = self.class.root_name if auto_assign_root?
+      @root = self.class.root_name if @root == true || @root.nil?
     end
 
     def attributes
@@ -142,11 +142,5 @@ module ActiveModel
       hash.merge! associations
     end
     alias serializable_object serializable_hash
-
-    private
-
-    def auto_assign_root?
-      @root == true || !@root && self.class._associations.any? { |a| a.embed_in_root? }
-    end
   end
 end

test/integration/action_controller/serialization_test.rb

@@ -14,7 +14,7 @@ module ActionController
       def test_render_using_implicit_serializer
         get :render_using_implicit_serializer
         assert_equal 'application/json', @response.content_type
-        assert_equal '{"name":"Name 1","description":"Description 1"}', @response.body
+        assert_equal '{"profile":{"name":"Name 1","description":"Description 1"}}', @response.body
       end
     end
 
@@ -36,7 +36,7 @@ module ActionController
       def test_render_using_implicit_serializer_and_scope
         get :render_using_implicit_serializer_and_scope
         assert_equal 'application/json', @response.content_type
-        assert_equal '{"name":"Name 1","description":"Description 1 - current_user"}', @response.body
+        assert_equal '{"profile":{"name":"Name 1","description":"Description 1 - current_user"}}', @response.body
       end
     end
 
@@ -62,7 +62,7 @@ module ActionController
       def test_render_using_implicit_serializer_and_explicit_scope
         get :render_using_implicit_serializer_and_explicit_scope
         assert_equal 'application/json', @response.content_type
-        assert_equal '{"name":"Name 1","description":"Description 1 - current_admin"}', @response.body
+        assert_equal '{"profile":{"name":"Name 1","description":"Description 1 - current_admin"}}', @response.body
       end
     end
 
@@ -88,7 +88,7 @@ module ActionController
       def test_render_overriding_serialization_scope
         get :render_overriding_serialization_scope
         assert_equal 'application/json', @response.content_type
-        assert_equal '{"name":"Name 1","description":"Description 1 - current_admin"}', @response.body
+        assert_equal '{"profile":{"name":"Name 1","description":"Description 1 - current_admin"}}', @response.body
       end
     end
 
@@ -112,7 +112,7 @@ module ActionController
       def test_render_calling_serialization_scope
         get :render_calling_serialization_scope
         assert_equal 'application/json', @response.content_type
-        assert_equal '{"name":"Name 1","description":"Description 1 - current_user"}', @response.body
+        assert_equal '{"profile":{"name":"Name 1","description":"Description 1 - current_user"}}', @response.body
       end
     end
 

test/integration/active_record/active_record_test.rb

@@ -22,7 +22,7 @@ module ActiveModel
 
       def test_attributes_serialization_using_as_json
         assert_equal({
-          'name' => 'Name 1', 'description' => 'Description 1'
+          'ar_profile' => { 'name' => 'Name 1', 'description' => 'Description 1' }
         }, @profile_serializer.as_json)
       end
     end

test/unit/active_model/serializer/attributes_test.rb

@@ -21,7 +21,7 @@ module ActiveModel
 
       def test_attributes_serialization_using_as_json
         assert_equal({
-          'name' => 'Name 1', 'description' => 'Description 1'
+          'profile' => { 'name' => 'Name 1', 'description' => 'Description 1' }
         }, @profile_serializer.as_json)
       end
     end

test/unit/active_model/serializer/has_many_test.rb

@@ -29,7 +29,7 @@ module ActiveModel
 
       def test_associations_embedding_ids_serialization_using_as_json
         assert_equal({
-          'title' => 'Title 1', 'body' => 'Body 1', 'comment_ids' => @post.comments.map { |c| c.object_id }
+          'post' => { 'title' => 'Title 1', 'body' => 'Body 1', 'comment_ids' => @post.comments.map { |c| c.object_id } }
         }, @post_serializer.as_json)
       end
 
@@ -50,7 +50,7 @@ module ActiveModel
       def test_associations_embedding_objects_serialization_using_as_json
         @association.embed = :objects
         assert_equal({
-          'title' => 'Title 1', 'body' => 'Body 1', 'comments' => [{ 'content' => 'C1' }, { 'content' => 'C2' }]
+          'post' => { 'title' => 'Title 1', 'body' => 'Body 1', 'comments' => [{ 'content' => 'C1' }, { 'content' => 'C2' }] }
         }, @post_serializer.as_json)
       end
 
@@ -63,7 +63,7 @@ module ActiveModel
         end
 
         assert_equal({
-          'title' => 'Title 1', 'body' => 'Body 1', 'comments' => [nil]
+          'post' => { 'title' => 'Title 1', 'body' => 'Body 1', 'comments' => [nil] }
         }, @post_serializer.as_json)
       end
 

test/unit/active_model/serializer/has_one_test.rb

@@ -29,7 +29,7 @@ module ActiveModel
 
       def test_associations_embedding_ids_serialization_using_as_json
         assert_equal({
-          'name' => 'Name 1', 'email' => 'mail@server.com', 'profile_id' => @user.profile.object_id
+          'user' => { 'name' => 'Name 1', 'email' => 'mail@server.com', 'profile_id' => @user.profile.object_id }
         }, @user_serializer.as_json)
       end
 
@@ -50,7 +50,7 @@ module ActiveModel
       def test_associations_embedding_objects_serialization_using_as_json
         @association.embed = :objects
         assert_equal({
-          'name' => 'Name 1', 'email' => 'mail@server.com', 'profiles' => [{ 'name' => 'N1', 'description' => 'D1' }]
+          'user' => { 'name' => 'Name 1', 'email' => 'mail@server.com', 'profiles' => [{ 'name' => 'N1', 'description' => 'D1' }] }
         }, @user_serializer.as_json)
       end
 
@@ -63,7 +63,7 @@ module ActiveModel
         end
 
         assert_equal({
-          'name' => 'Name 1', 'email' => 'mail@server.com', 'profiles' => [nil]
+          'user' => { 'name' => 'Name 1', 'email' => 'mail@server.com', 'profiles' => [nil] }
         }, @user_serializer.as_json)
       end