diff --git a/test/test_kramdown.rb b/test/test_kramdown.rb
index f7b5ea70..62b70ddd 100644
--- a/test/test_kramdown.rb
+++ b/test/test_kramdown.rb
@@ -1,6 +1,7 @@
 # frozen_string_literal: true
 
 require "helper"
+require "rouge"
 
 class TestKramdown < JekyllUnitTest
   context "kramdown" do