--- a/config/environments/test.rb	Sat Apr 14 04:19:29 2018 +0900
+++ b/config/environments/test.rb	Sat Apr 14 04:19:52 2018 +0900
@@ -15,7 +15,7 @@
   # 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=3600"
+    'Cache-Control' => "public, max-age=#{1.hour.to_i}"
   }
 
   # Show full error reports and disable caching.
@@ -27,12 +27,9 @@
 
   # Disable request forgery protection in test environment.
   config.action_controller.allow_forgery_protection = false
-  # config.action_mailer.perform_caching = false
 
-  # Tell Action Mailer not to deliver emails to the real world.
-  # The :test delivery method accumulates sent emails in the
-  # ActionMailer::Base.deliveries array.
-  # config.action_mailer.delivery_method = :test
+  # Store uploaded files on the local file system in a temporary directory
+  config.active_storage.service = :test
 
   # Print deprecation notices to the stderr.
   config.active_support.deprecation = :stderr