Extract attributes filtering from serializer into adapter.

test/adapter/json_api/collection_test.rb

@@ -58,8 +58,10 @@ module ActiveModel
           end
 
           def test_limiting_fields
-            @adapter = ActiveModel::Serializer::Adapter::JsonApi.new(@serializer, fields: ['title'])
-
+            actual = ActiveModel::SerializableResource.new(
+              [@first_post, @second_post], adapter: :json_api,
+                                           fields: { posts: ['title'] })
+                     .serializable_hash
             expected = [
               {
                 id: '1',
@@ -86,7 +88,7 @@ module ActiveModel
                 }
               }
             ]
-            assert_equal(expected, @adapter.serializable_hash[:data])
+            assert_equal(expected, actual[:data])
           end
         end
       end

test/serializers/attributes_test.rb

@@ -18,11 +18,6 @@ module ActiveModel
           @profile_serializer.class._attributes)
       end
 
-      def test_attributes_with_fields_option
-        assert_equal({ name: 'Name 1' },
-          @profile_serializer.attributes(fields: [:name]))
-      end
-
       def test_attributes_inheritance_definition
         assert_equal([:id, :body], @serializer_klass._attributes)
       end

test/serializers/fieldset_test.rb

@@ -4,22 +4,11 @@ module ActiveModel
   class Serializer
     class FieldsetTest < Minitest::Test
       def test_fieldset_with_hash
-        fieldset = ActiveModel::Serializer::Fieldset.new({ 'post' => %w(id title), 'coment' => ['body'] })
+        fieldset = ActiveModel::Serializer::Fieldset.new('post' => %w(id title), 'comment' => ['body'])
+        expected = { :post => [:id, :title], :comment => [:body] }
 
-        assert_equal(
-          { :post => [:id, :title], :coment => [:body] },
-          fieldset.fields
-        )
-      end
-
-      def test_fieldset_with_array_of_fields_and_root_name
-        fieldset = ActiveModel::Serializer::Fieldset.new(['title'], 'post')
-
-        assert_equal(
-          { :post => [:title] },
-          fieldset.fields
-        )
+        assert_equal(expected, fieldset.fields)
       end
     end
   end
-end
+end