Merge branch 'leandrocp-add-top-level-links'

Needs followup
- https://github.com/rails-api/active_model_serializers/pull/1018#discussion_r51733900
- https://github.com/rails-api/active_model_serializers/pull/1018#discussion_r51734779
- https://github.com/rails-api/active_model_serializers/pull/1018#discussion_r51735145
- https://github.com/rails-api/active_model_serializers/pull/1018#discussion_r51735218

test/action_controller/serialization_test.rb

@@ -45,6 +45,16 @@ module ActionController
           render json: @profiles, meta: { total: 10 }
         end
 
+        def render_array_using_implicit_serializer_and_links
+          with_adapter ActiveModel::Serializer::Adapter::JsonApi do
+            @profiles = [
+              Profile.new(name: 'Name 1', description: 'Description 1', comments: 'Comments 1')
+            ]
+
+            render json: @profiles, links: { self: 'http://example.com/api/profiles/1' }
+          end
+        end
+
         def render_object_with_cache_enabled
           @comment = Comment.new(id: 1, body: 'ZOMG A COMMENT')
           @author  = Author.new(id: 1, name: 'Joao Moura.')
@@ -254,6 +264,29 @@ module ActionController
         assert_equal expected.to_json, @response.body
       end
 
+      def test_render_array_using_implicit_serializer_and_links
+        get :render_array_using_implicit_serializer_and_links
+
+        expected = {
+          data: [
+            {
+              id: assigns(:profiles).first.id.to_s,
+              type: 'profiles',
+              attributes: {
+                name: 'Name 1',
+                description: 'Description 1'
+              }
+            }
+          ],
+          links: {
+            self: 'http://example.com/api/profiles/1'
+          }
+        }
+
+        assert_equal 'application/json', @response.content_type
+        assert_equal expected.to_json, @response.body
+      end
+
       def test_render_with_cache_enable
         expected = {
           id: 1,

test/adapter/json_api/links_test.rb

@@ -59,6 +59,15 @@ module ActiveModel
             assert_equal(expected, hash[:links])
           end
 
+          def test_nil_toplevel_links
+            hash = ActiveModel::SerializableResource.new(
+              @post,
+              adapter: :json_api,
+              links: nil
+            ).serializable_hash
+            assert_equal(nil, hash[:links])
+          end
+
           def test_resource_links
             hash = serializable(@author, adapter: :json_api).serializable_hash
             expected = {