prepare

# File activestorage/lib/active_storage/fixture_set.rb, line 70
    def prepare(instance, **attributes)
      io = file_fixture(instance.filename.to_s).open
      instance.unfurl(io)
      instance.assign_attributes(attributes)
      instance.upload_without_unfurling(io)

      instance.attributes.transform_values { |value| value.is_a?(Hash) ? value.to_json : value }.compact.to_json
    end