Correct relationships data

lib/ams/serializer.rb

@@ -108,9 +108,7 @@ module AMS
           end
 
           def #{relation_name}
-            related_#{relation_name}_ids.map do |id|
-              relationship_object(id, "#{type}")
-            end
+            relationship_object(related_#{relation_name}_ids, "#{type}")
           end
         METHOD
       end
@@ -183,10 +181,19 @@ module AMS
       self.class._relations
     end
 
-    def relationship_object(id, type)
-      {
-        "data": { "id": id, "type": type }, # resource linkage
-      }
+    def relationship_object(id_or_ids, type)
+      data =
+        if id_or_ids.respond_to?(:to_ary)
+          id_or_ids.map { |id| relationship_data(id, type) }
+        else
+          relationship_data(id_or_ids, type)
+        end
+      { "data": data }
+    end
+
+    # resource linkage
+    def relationship_data(id, type)
+      { "id": id, "type": type }
     end
 
     def dump(obj)

test/unit/serializer/as_json_test.rb

@@ -30,7 +30,7 @@ module AMS
           id: 1, type: :profiles,
           attributes: { name: "name", summary: "description" },
           relationships:
-          { child_models: [{ data: { id: 2, type: "comments" } }] }
+          { child_models: { data: [{ id: 2, type: "comments" }] } }
         }
         assert_equal expected, @serializer_instance.as_json
       end
@@ -40,7 +40,7 @@ module AMS
           id: 1, type: :profiles,
           attributes: { name: "name", summary: "description" },
           relationships:
-          { child_models: [{ data: { id: 2, type: "comments" } }] }
+          { child_models: { data: [{ id: 2, type: "comments" }] } }
         }.to_json
         assert_equal expected, @serializer_instance.to_json
       end

test/unit/serializer/relationships_test.rb

@@ -20,18 +20,18 @@ module AMS
 
       def test_model_instance_relations
         expected_relations = {
-          child_models: [{
-            data: { type: "comments", id: 2 }
-          }]
+          child_models: {
+            data: [{ type: "comments", id: 2 }]
+          }
         }
         assert_equal expected_relations, @serializer_instance.relations
       end
 
-      def test_model_instance_relationship_object
+      def test_model_instance_relationship_data
         expected = {
-          data: { type: :bananas, id: 5 }
+          type: :bananas, id: 5
         }
-        assert_equal expected, @serializer_instance.relationship_object(5, :bananas)
+        assert_equal expected, @serializer_instance.relationship_data(5, :bananas)
       end
     end
   end