diff --git a/tests/CartTest.php b/tests/CartTest.php
index e1ddfa4..3d9fcf4 100644
--- a/tests/CartTest.php
+++ b/tests/CartTest.php
@@ -366,8 +366,8 @@ class CartTest extends TestCase
         $cart = $this->getCart();
 
         $cart->add(new BuyableProduct([
-            'name'  => null,
-            'title' => null,
+            'name'  => '',
+            'title' => '',
         ]));
 
         $cart->update('027c91341fd5cf4d2579b49c4b6a90da', ['description' => 'Different description']);