diff --git a/src/tests/presale/test_cart.py b/src/tests/presale/test_cart.py
index ce52409b8..5b1658770 100644
--- a/src/tests/presale/test_cart.py
+++ b/src/tests/presale/test_cart.py
@@ -1374,46 +1374,59 @@ class CartTest(CartTestMixin, TestCase):
             self.assertFalse(CartPosition.objects.filter(id=cp1.id).exists())
 
     def test_expired_renew_fails_partially_and_add_succeeds(self):
+        start_time = datetime.datetime(2024, 1, 1, 10, 00, 00, tzinfo=datetime.timezone.utc)
+        expires = start_time + self.cart_reservation_time
+        max_extend = start_time + 11 * self.cart_reservation_time
         self.quota_tickets.size = 0
         self.quota_tickets.save()
         with scopes_disabled():
             cp1 = CartPosition.objects.create(
                 event=self.event, cart_id=self.session_key, item=self.ticket,
-                price=23, expires=now() - timedelta(minutes=10), max_extend=now() + 10 * self.cart_reservation_time
+                price=23, expires=expires, max_extend=max_extend
             )
             cp2 = CartPosition.objects.create(
                 event=self.event, cart_id=self.session_key, item=self.shirt, variation=self.shirt_blue,
-                price=23, expires=now() - timedelta(minutes=10), max_extend=now() + 10 * self.cart_reservation_time
+                price=23, expires=expires, max_extend=max_extend
             )
-        response = self.client.post('/%s/%s/cart/add' % (self.orga.slug, self.event.slug), {
-            'variation_%d_%d' % (self.shirt.id, self.shirt_red.id): '1',
-        }, follow=True)
-        doc = BeautifulSoup(response.rendered_content, "lxml")
-        self.assertIn('no longer available', doc.select('.alert-danger')[0].text)
-        with scopes_disabled():
-            self.assertFalse(CartPosition.objects.filter(id=cp1.id).exists())
-            self.assertTrue(CartPosition.objects.filter(id=cp2.id).exists())
-            self.assertTrue(CartPosition.objects.filter(variation_id=self.shirt_red.id).exists())
+        with freezegun.freeze_time(max_extend + timedelta(hours=1)):
+            response = self.client.post('/%s/%s/cart/add' % (self.orga.slug, self.event.slug), {
+                'variation_%d_%d' % (self.shirt.id, self.shirt_red.id): '1',
+            }, follow=True)
+            doc = BeautifulSoup(response.rendered_content, "lxml")
+            self.assertIn('no longer available', doc.select('.alert-danger')[0].text)
+            with scopes_disabled():
+                self.assertFalse(CartPosition.objects.filter(id=cp1.id).exists())
+                cp2.refresh_from_db()
+                self.assertEqual(cp2.expires, now() + self.cart_reservation_time)
+                self.assertEqual(cp2.max_extend, now() + 11 * self.cart_reservation_time)
+                cp3 = CartPosition.objects.get(variation_id=self.shirt_red.id)
+                self.assertEqual(cp2.expires, now() + self.cart_reservation_time)
+                self.assertEqual(cp2.max_extend, now() + 11 * self.cart_reservation_time)
 
     def test_expired_cart_extend_fails_partially(self):
+        start_time = datetime.datetime(2024, 1, 1, 10, 00, 00, tzinfo=datetime.timezone.utc)
+        max_extend = start_time + 11 * self.cart_reservation_time
         self.quota_tickets.size = 0
         self.quota_tickets.save()
         with scopes_disabled():
             cp1 = CartPosition.objects.create(
                 event=self.event, cart_id=self.session_key, item=self.ticket,
-                price=23, expires=now() - timedelta(minutes=10), max_extend=now() - timedelta(minutes=10)
+                price=23, expires=max_extend, max_extend=max_extend
             )
             cp2 = CartPosition.objects.create(
                 event=self.event, cart_id=self.session_key, item=self.shirt, variation=self.shirt_blue,
-                price=23, expires=now() - timedelta(minutes=10), max_extend=now() - timedelta(minutes=10)
+                price=23, expires=max_extend, max_extend=max_extend
             )
-        response = self.client.post('/%s/%s/cart/extend' % (self.orga.slug, self.event.slug), {
-        }, follow=True)
-        doc = BeautifulSoup(response.rendered_content, "lxml")
-        self.assertIn('no longer available', doc.select('.alert-danger')[0].text)
-        with scopes_disabled():
-            self.assertFalse(CartPosition.objects.filter(id=cp1.id).exists())
-            self.assertTrue(CartPosition.objects.filter(id=cp2.id).exists())
+        with freezegun.freeze_time(max_extend + timedelta(hours=1)):
+            response = self.client.post('/%s/%s/cart/extend' % (self.orga.slug, self.event.slug), {
+            }, follow=True)
+            doc = BeautifulSoup(response.rendered_content, "lxml")
+            self.assertIn('no longer available', doc.select('.alert-danger')[0].text)
+            with scopes_disabled():
+                self.assertFalse(CartPosition.objects.filter(id=cp1.id).exists())
+                cp2.refresh_from_db()
+                self.assertEqual(cp2.expires, now() + self.cart_reservation_time)
+                self.assertEqual(cp2.max_extend, now() + 11 * self.cart_reservation_time)
 
     def test_subevent_renew_expired_successfully(self):
         self.event.has_subevents = True