From c9a62db774c57ec5b2b057787aedb84a401a1813 2016-04-06 07:02:11
From: Christopher Neugebauer <chrisjrn@gmail.com>
Date: 2016-04-06 07:02:11
Subject: [PATCH] Resolves #17 - cannot generate invoice if there are no product items
---

diff --git a/registrasion/controllers/invoice.py b/registrasion/controllers/invoice.py
index fdea324bfd3ac14ac000ff8c5265e5212512a917..dafb134b9dd8fc6cdf39bde6770d11b00615e6a2 100644
--- a/registrasion/controllers/invoice.py
+++ b/registrasion/controllers/invoice.py
@@ -67,8 +67,11 @@ class InvoiceController(object):
         )
         invoice.save()
 
-        # TODO: calculate line items.
         product_items = rego.ProductItem.objects.filter(cart=cart)
+
+        if len(product_items) == 0:
+            raise ValidationError("Your cart is empty.")
+
         product_items = product_items.order_by(
             "product__category__order", "product__order"
         )