Optimize range products reordering (#4010)

* feat :star: optimize range products reordering

* test :white_check_mark: add test to verify range product reordering

* fix :wrench: remove local settings from test settings

* test :white_check_mark: update product reordering test

src/oscar/apps/dashboard/ranges/views.py

         """
         Save the order of the products within range.
         """
-        range = get_object_or_404(Range, pk=self.kwargs['pk'])
-        for index, item in enumerate(order):
-            entry = RangeProduct.objects.get(range=range, product__pk=item)
-            if entry.display_order != index:
-                entry.display_order = index
-                entry.save()
+        range_products = RangeProduct.objects.filter(
+            range_id=self.kwargs['pk'], product_id__in=order
+        )
+        for range_product in range_products:
+            range_product.display_order = order.index(
+                str(range_product.product_id)
+            )
+        RangeProduct.objects.bulk_update(range_products, ["display_order"])

tests/functional/dashboard/test_range.py

+import random
+
 from django.contrib.messages.constants import SUCCESS, WARNING
 from django.test import TestCase
 from django.urls import reverse
         self.assertTrue(self.range.contains_product(self.child1))
         self.assertTrue(self.range.contains_product(self.child2))
         self.assertFalse(self.range.contains_product(self.parent))
+
+
+class RangeReorderViewTest(WebTestCase):
+    is_staff = True
+    csrf_checks = False
+
+    def setUp(self):
+        super().setUp()
+        self.range = Range.objects.create(name='dummy')
+        self.url = reverse('dashboard:range-reorder', args=(self.range.id,))
+        self.product1 = create_product()
+        self.product2 = create_product()
+        self.product3 = create_product()
+        self.range.included_products.set([
+            self.product1, self.product2, self.product3])
+
+    def test_range_product_reordering(self):
+        product_order = list(self.range.rangeproduct_set.values_list(
+            'product_id', flat=True))
+        random.shuffle(product_order)
+        data = {'product': product_order}
+        self.post(self.url, params=data)
+        new_product_order = list(self.range.rangeproduct_set.values_list(
+            'product_id', flat=True).order_by('display_order'))
+        self.assertEqual(new_product_order, product_order)