diff --git a/src/components/RouteResults.test.jsx b/src/components/RouteResults.test.jsx
index 542d5fa..0a8776c 100644
--- a/src/components/RouteResults.test.jsx
+++ b/src/components/RouteResults.test.jsx
@@ -118,7 +118,9 @@ describe('RouteResults - mode label', () => {
   });
 
   it('falls back to the mode prop when the route does not carry one', () => {
-    const { mode, ...withoutMode } = measuredRoute;
+    const withoutMode = { ...measuredRoute };
+    delete withoutMode.mode;
+
     render(<RouteResults routes={[withoutMode]} mode="biking" pollutionDataAvailable />);
     expect(screen.getByText('biking')).toBeInTheDocument();
   });