diff --git a/test/test_utils.rb b/test/test_utils.rb
index f102b7a6..8d5ba7a8 100644
--- a/test/test_utils.rb
+++ b/test/test_utils.rb
@@ -182,6 +182,10 @@ class TestUtils < JekyllUnitTest
       assert_equal "the-_config.yml-file", Utils.slugify("The _config.yml file?", mode: "pretty")
     end
 
+    should "replace everything else but ASCII characters" do
+      assert_equal "the-config.yml-file", Utils.slugify("The _config.yml file?", mode: "ascii")
+    end
+
     should "only replace whitespace if mode is raw" do
       assert_equal "the-_config.yml-file?", Utils.slugify("The _config.yml file?", mode: "raw")
     end