fix root path and tests

app/models/merged/shared_base.rb

@@ -11,7 +11,7 @@ module Merged
         raise "#{full} contained #{got.class}, not Array" unless got.class == Array
         got
       end
-      loaded_files.sum
+      loaded_files.first + loaded_files.last
     end
   end
 end

app/models/merged/view_base.rb

@@ -5,7 +5,7 @@ module Merged
   # and the fact that they persist in ActiveYaml
 
   class ViewBase < ActiveBase
-    set_root_path Merged.data_dir
+    set_root_path Rails.root.join(Merged.data_dir)
     include ActiveHash::Associations
 
     belongs_to :image , class_name: "Merged::Image"

test/dummy/merged/cards.yml

@@ -9,7 +9,7 @@
     background: solid_blue
     text_color: white
     align: left
-  :updated_at: 2023-01-05 21:33:46.577677395 +02:00
+  :updated_at: 2023-01-29 18:34:15.909539509 +02:00
   :section_id: 11
   :index: 1
   :image_id: 35

test/dummy/merged/option_definitions.yml

@@ -0,0 +1 @@
+--- []

test/test_helper.rb

@@ -7,6 +7,7 @@ require 'capybara/rails'
 require 'capybara/minitest'
 require "devise"
 require "devise/test/integration_helpers"
+require "merged"
 
 Dir[Merged::Engine.root.join("test/helpers/**/*.rb")].each { |f| require f }