diff --git a/tests/media.rs b/tests/media.rs
index b6f32aa..6d395f8 100644
--- a/tests/media.rs
+++ b/tests/media.rs
@@ -12,3 +12,7 @@ test!(
     "a {\n  @media foo {\n  color: red;\n  }\n}\n",
     "@media foo {\n  a {\n    color: red;\n  }\n}\n"
 );
+test!(
+    basic_unknown_at_rule,
+    "@foo {\n  a {\n    color: red;\n  }\n}\n"
+);