diff --git a/tests/CouponOrderTest.php b/tests/CouponOrderTest.php
new file mode 100644
index 0000000..8c33d4f
--- /dev/null
+++ b/tests/CouponOrderTest.php
@@ -0,0 +1,69 @@
+<?php
+
+namespace Bazaar\Tests;
+
+use Bazaar\Core\Session;
+use Bazaar\Repositories\CouponRepository;
+use Bazaar\Repositories\OrderRepository;
+use Bazaar\Repositories\ProductRepository;
+use Bazaar\Repositories\UserRepository;
+use Bazaar\Services\Cart;
+use Bazaar\Services\CouponService;
+use Bazaar\Services\OrderService;
+
+final class CouponOrderTest extends DatabaseTestCase
+{
+    private CouponRepository $coupons;
+    private CouponService $couponService;
+    private OrderRepository $orders;
+    private ProductRepository $products;
+    private OrderService $service;
+    private int $userId;
+
+    protected function setUp(): void
+    {
+        parent::setUp();
+        $this->coupons = new CouponRepository($this->db);
+        $this->couponService = new CouponService($this->coupons);
+        $this->orders = new OrderRepository($this->db);
+        $this->products = new ProductRepository($this->db);
+        $this->service = new OrderService($this->db, $this->orders, $this->products, null, $this->coupons);
+        $this->userId = (new UserRepository($this->db))->create('coup@bazaar.test', 'hash', 'Coup');
+    }
+
+    public function testDiscountReducesStoredTotalAndIsRedeemedOnPaid(): void
+    {
+        $couponId = $this->coupons->create([
+            'code' => 'TENOFF',
+            'type' => 'percent',
+            'value' => 10,
+            'minSubtotalCents' => 0,
+            'maxRedemptions' => 5,
+            'startsAt' => null,
+            'expiresAt' => null,
+            'isActive' => true,
+        ]);
+
+        $productId = $this->seedProduct('Chair', 10000, 10);
+        $cart = new Cart(new Session(), $this->products);
+        $cart->add($productId, 1);
+
+        $evaluation = $this->couponService->evaluate('TENOFF', $cart->totalCents());
+        $this->assertTrue($evaluation->isValid());
+        $this->assertSame(1000, $evaluation->discountCents);
+
+        $orderId = $this->service->createFromCart($this->userId, $cart, 'usd', [
+            'discountCents' => $evaluation->discountCents,
+            'couponCode' => 'TENOFF',
+        ]);
+
+        $order = $this->orders->find($orderId);
+        $this->assertSame(9000, (int) $order['totalCents']);
+        $this->assertSame(1000, (int) $order['discountCents']);
+        $this->assertSame('TENOFF', $order['couponCode']);
+        $this->assertSame(0, (int) $this->coupons->find($couponId)['redeemedCount']);
+
+        $this->service->markPaid($orderId);
+        $this->assertSame(1, (int) $this->coupons->find($couponId)['redeemedCount']);
+    }
+}