diff --git a/src/engine.rs b/src/engine.rs
index 48d0167..802d909 100644
--- a/src/engine.rs
+++ b/src/engine.rs
@@ -2348,7 +2348,7 @@ mod tests {
 
         // Dashboard side: rate() over a 2s window, read at the series' own last timestamp.
         let parsed = promql::parse_query("rate(requests[2s])").unwrap();
-        let series = evaluate_promql(&index, &parsed, None, None);
+        let series = evaluate_promql(&index, &parsed, None, None).unwrap();
         assert_eq!(series.len(), 1);
         let (_, dashboard_rate) = *series[0].points.last().unwrap();