diff --git a/src/simulator/crates/mc-player-api/src/wire.rs b/src/simulator/crates/mc-player-api/src/wire.rs
index 836dd541..096c0dc8 100644
--- a/src/simulator/crates/mc-player-api/src/wire.rs
+++ b/src/simulator/crates/mc-player-api/src/wire.rs
@@ -365,7 +365,9 @@ mod tests {
         let resp = Response::Err {
             id: None,
             ok: ErrMarker,
-            error: ActionError::UnknownUnit("u_99".into()),
+            error: ActionError::UnknownUnit {
+                unit_id: "u_99".into(),
+            },
         };
         let json = serde_json::to_string(&resp).unwrap();
         assert!(json.contains("\"ok\":false"), "json={}", json);