add shopify rubocop

config/environments/test.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "active_support/core_ext/integer/time"
 
 # The test environment is used exclusively to run your application's
@@ -19,7 +20,7 @@ Rails.application.configure do
   # Configure public file server for tests with Cache-Control for performance.
   config.public_file_server.enabled = true
   config.public_file_server.headers = {
-    'Cache-Control' => "public, max-age=#{1.hour.to_i}"
+    "Cache-Control" => "public, max-age=#{1.hour.to_i}",
   }
 
   # Show full error reports and disable caching.