diff --git a/apps/pr-reviewer/fixtures/demo-pr/cart-total.ts b/apps/pr-reviewer/fixtures/demo-pr/cart-total.ts
index c694360..b6c86c1 100644
--- a/apps/pr-reviewer/fixtures/demo-pr/cart-total.ts
+++ b/apps/pr-reviewer/fixtures/demo-pr/cart-total.ts
@@ -1,10 +1,13 @@
-export function cartTotal(items: { price: number; qty: number }[]): number {
+export type CartItem = { price: number; qty: number; discountCents?: number };
+
+export function cartTotal(items: CartItem[]): number {
   let total = 0;
   for (let i = 0; i < items.length; i++) {
     if (items[i].qty < 0) {
       throw new RangeError(`Negative quantity for item ${i}`);
     }
-    total += items[i].price * items[i].qty;
+    const line = items[i].price * items[i].qty;
+    total += line - (items[i].discountCents ?? 0);
   }
   return total;
 }