Fix set_key_transform's set_type to give priority to pre-set value

Author: sakuraineed

lib/fast_jsonapi/object_serializer.rb

@@ -143,7 +143,11 @@ def set_key_transform(transform_name)
         self.transform_method = mapping[transform_name.to_sym]
 
         # ensure that the record type is correctly transformed
-        set_type(reflected_record_type) if reflected_record_type
+        if record_type
+          set_type(record_type)
+        elsif reflected_record_type
+          set_type(reflected_record_type)
+        end
       end
 
       def run_key_transform(input)

spec/lib/object_serializer_class_methods_spec.rb

@@ -411,4 +411,22 @@ def year_since_release_calculator(release_year)
       it_behaves_like 'returning key transformed hash', :movie_type, :underscore_movie_type, :release_year
     end
   end
+
+  describe '#set_key_transform after #set_type' do
+    subject(:serializable_hash) { MovieSerializer.new(movie).serializable_hash }
+
+    before do
+      MovieSerializer.set_type :foo_bar
+      MovieSerializer.set_key_transform :camel
+    end
+
+    after do
+      MovieSerializer.set_type :movie
+      MovieSerializer.transform_method = nil
+    end
+
+    it 'returns correct hash which type equals transformed set_type value' do
+      expect(serializable_hash[:data][:type]).to eq :FooBar
+    end
+  end
 end