diff --git a/guides/Rakefile b/guides/Rakefile
index 58efdefa13181..0e6556f3b863b 100644
--- a/guides/Rakefile
+++ b/guides/Rakefile
@@ -79,7 +79,7 @@ task :test do
   counter = templates.count do |file|
     puts "--- Running #{file}"
 
-    if RUBY_VERSION < 2.7.0 && file.end_with?("_main.rb)
+    if RUBY_VERSION < "2.7.0" && file.end_with?("_main.rb")
       1
     else
       Bundler.clean_system(Gem.ruby, "-w", file) ||