1 files changed, 37 insertions, 0 deletions
diff --git a/internal/world/rekey_objects_test.go b/internal/world/rekey_objects_test.go
new file mode 100644
index 0000000..7ee2de3
--- /dev/null
+++ b/internal/world/rekey_objects_test.go
@@ -0,0 +1,37 @@
+package world
+
+import "testing"
+
+// TestRekeyRoomsUpdatesObjStateRoomID: object lookups filter on ObjState.RoomID
+// while GetObjState looks up the map key, so the invariant
+// mapKey == ObjStateKey(st.RoomID, ...) must survive a rekey. Leaving RoomID
+// stale makes room objects vanish from a renamed/swapped room for the rest of
+// the process and lets TickObjWander create a duplicate entry for the state.
+func TestRekeyRoomsUpdatesObjStateRoomID(t *testing.T) {
+	w := New(t.TempDir())
+	w.objStates[w.ObjStateKey(1, "anvil", 0)] = &ObjState{
+		RoomID:      1,
+		DefID:       "anvil",
+		Index:       0,
+		WanderRooms: []int{1, 5, 9},
+	}
+
+	w.RekeyRooms(map[int]int{1: 3, 5: 7})
+
+	inst := w.GetObjState(3, "anvil", 0)
+	if inst == nil {
+		t.Fatal("object state lost after rekey")
+	}
+	if inst.RoomID != 3 {
+		t.Fatalf("ObjState.RoomID = %d, want 3 (map key and state desynchronised)", inst.RoomID)
+	}
+	if got := inst.WanderRooms; len(got) != 3 || got[0] != 3 || got[1] != 7 || got[2] != 9 {
+		t.Fatalf("WanderRooms after rekey = %v, want [3 7 9]", got)
+	}
+	if got := w.AllObjInstances(3); len(got) != 1 {
+		t.Fatalf("AllObjInstances(3) = %d entries, want 1 (object invisible in renamed room)", len(got))
+	}
+	if got := w.AllObjInstances(1); len(got) != 0 {
+		t.Fatalf("AllObjInstances(1) = %d entries, want 0 (stale old room)", len(got))
+	}
+}