Merge branch 'master' into domitian-move-namespace-of-adapter-to-active-model-serializers

Conflicts:
	CHANGELOG.md
	lib/active_model/serializer/adapter/attributes.rb
	lib/active_model/serializer/adapter/cached_serializer.rb
	lib/active_model/serializer/adapter/fragment_cache.rb
	lib/active_model/serializer/adapter/json_api.rb
	lib/active_model/serializer/adapter/json_api/link.rb
	test/adapter/fragment_cache_test.rb
	test/adapter/json_api/links_test.rb
	test/adapter/json_api/resource_type_config_test.rb

test/adapter/json_api/links_test.rb

@@ -20,7 +20,7 @@ module ActiveModelSerializers
 
         def setup
           @post = Post.new(id: 1337, comments: [], author: nil)
-          @author = LinkAuthor.new(id: 1337)
+          @author = LinkAuthor.new(id: 1337, posts: [@post])
         end
 
         def test_toplevel_links
@@ -46,6 +46,24 @@ module ActiveModelSerializers
           assert_equal(expected, hash[:links])
         end
 
+        def test_nil_toplevel_links
+          hash = ActiveModel::SerializableResource.new(
+            @post,
+            adapter: :json_api,
+            links: nil
+          ).serializable_hash
+          refute hash.key?(:links), 'No links key to be output'
+        end
+
+        def test_nil_toplevel_links_json_adapter
+          hash = ActiveModel::SerializableResource.new(
+            @post,
+            adapter: :json,
+            links: nil
+          ).serializable_hash
+          refute hash.key?(:links), 'No links key to be output'
+        end
+
         def test_resource_links
           hash = serializable(@author, adapter: :json_api).serializable_hash
           expected = {