diff --git a/crates/domain/src/object.rs b/crates/domain/src/object.rs
index 41b1829..474f787 100644
--- a/crates/domain/src/object.rs
+++ b/crates/domain/src/object.rs
@@ -180,6 +180,11 @@ mod tests {
                 to: Draft
             })
         );
+        // the Display message is the user-visible surface of the error
+        assert_eq!(
+            Draft.transition_to(Public).unwrap_err().to_string(),
+            "illegal visibility transition: draft -> public"
+        );
     }
 
     #[test]