test(domain): pin Visibility serde output to as_str

crates/domain/src/object.rs

@@ -95,4 +95,14 @@ mod tests {
         assert_eq!(Visibility::from_db("secret"), None);
         assert_eq!(Visibility::default(), Visibility::Draft);
     }
+
+    #[test]
+    fn visibility_serde_matches_as_str() {
+        for v in [Visibility::Draft, Visibility::Internal, Visibility::Public] {
+            assert_eq!(
+                serde_json::to_value(v).unwrap(),
+                serde_json::Value::String(v.as_str().to_owned())
+            );
+        }
+    }
 }