diff --git a/test/simulation_test.dart b/test/simulation_test.dart
index 7b8bf82..1f99ed1 100644
--- a/test/simulation_test.dart
+++ b/test/simulation_test.dart
@@ -24,7 +24,7 @@ void main() {
     test("creates a new underlying grid on resizing", () {
       var oldMap = sut.map;
       sut.gridSize = Point(10, 10);
-      expect(sut.map, isNot(oldMap));
+      expect(sut.map, isNot(same(oldMap)));
     });
   });
   group("reset", () {