Updated use_startup_css to check if we are in Test

app/helpers/application_helper.rb

@@ -236,11 +236,11 @@ module ApplicationHelper
   end
 
   def use_startup_css?
-    Feature.enabled?(:startup_css)
+    Feature.enabled?(:startup_css) && !Rails.env.test?
   end
 
   def stylesheet_link_tag_defer(path)
-    if use_startup_css? && !Rails.env.test?
+    if use_startup_css?
       stylesheet_link_tag(path, media: "print")
     else
       stylesheet_link_tag(path, media: "all")