diff --git a/src/lib.rs b/src/lib.rs
index acc8164..d1e33c1 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -226,6 +226,9 @@ mod tests {
 
     #[test]
     fn bnf_representation() {
+        let bnf = json_value().bnf().unwrap();
+        assert_eq!(bnf, Bnf::Production);
+
         let bnf = json_object().bnf().unwrap();
         assert_eq!(bnf, Bnf::Production);
     }