Clean up and kitten saving in test code.

Replace numbered variables with a list comprehension
Create the product image in one line using .create(**kwags) instead
    of instantiating and then saving.

oscar/test/factories.py

@@ -102,24 +102,19 @@ def create_product_image(product=None,
                          ):
     if not product:
         product = create_product()
-    if not original:
-        original = None  # FIXME change?
     if not display_order:
         if not product.images.all():
             display_order = 0
         else:
             display_order = max(
                 [i.display_order for i in product.images.all()])+1
 
-    i_kwargs = {'product_id': product.id,
-                'original': original,
-                'display_order': display_order,
-                'caption': caption, }
+    kwargs = {'product_id': product.id,
+              'original': original,
+              'display_order': display_order,
+              'caption': caption, }
 
-    product_image = ProductImage(**i_kwargs)
-    product_image.save()
-
-    return product_image
+    return ProductImage.objects.create(**kwargs)
 
 
 def create_basket(empty=False):

tests/integration/catalogue/product_image_tests.py

@@ -5,22 +5,12 @@
 
 class TestProductImages(TestCase):
 
-    def setUp(self):
-        self.product = factories.create_product()
-        self.im_1 = factories.create_product_image(product=self.product,
-                                                   display_order=0)
-        self.im_2 = factories.create_product_image(product=self.product,
-                                                   display_order=1)
-        self.im_3 = factories.create_product_image(product=self.product,
-                                                   display_order=2)
-        self.im_4 = factories.create_product_image(product=self.product,
-                                                   display_order=3)
-
-    def tearDown(self):
-        self.product.delete()
-
     def test_images_are_in_consecutive_order(self):
-        self.product.images.all()[2].delete()
+        product = factories.create_product()
+        images = [factories.create_product_image(
+                  product=product, display_order=i) for i in range(4)]
+
+        product.images.all()[2].delete()
 
-        for idx, im in enumerate(self.product.images.all()):
+        for idx, im in enumerate(product.images.all()):
             self.assertEqual(im.display_order, idx)