Invoices now automatically void themselves if their cart is out of date

registrasion/controllers/invoice.py

@@ -11,6 +11,7 @@ class InvoiceController(object):
 
     def __init__(self, invoice):
         self.invoice = invoice
+        self.update_validity() # Make sure this invoice is up-to-date
 
     @classmethod
     def for_cart(cls, cart):
@@ -24,6 +25,10 @@ class InvoiceController(object):
         except ObjectDoesNotExist:
             cart_controller = CartController(cart)
             cart_controller.validate_cart()  # Raises ValidationError on fail.
+
+            # Void past invoices for this cart
+            invoices = rego.Invoice.objects.filter(cart=cart).update(void=True)
+
             invoice = cls._generate(cart)
 
         return InvoiceController(invoice)
@@ -91,19 +96,17 @@ class InvoiceController(object):
 
         return invoice
 
-    def is_valid(self):
-        ''' Returns true if the attached invoice is not void and it represents
-        a valid cart. '''
-        if self.invoice.void:
-            return False
+    def update_validity(self):
+        ''' Updates the validity of this invoice if the cart it is attached to
+        has updated. '''
         if self.invoice.cart is not None:
             if self.invoice.cart.revision != self.invoice.cart_revision:
-                return False
-        return True
+                self.void()
 
     def void(self):
         ''' Voids the invoice. '''
         self.invoice.void = True
+        self.invoice.save()
 
     def pay(self, reference, amount):
         ''' Pays the invoice by the given amount. If the payment

registrasion/tests/test_invoice.py

@@ -27,11 +27,17 @@ class InvoiceTestCase(RegistrationCartTestCase):
         # That invoice should have a value equal to cost of PROD_1
         self.assertEqual(self.PROD_1.price, invoice_1.invoice.value)
 
-        # Adding item to cart should void all active invoices and produce
-        # a new invoice
+        # Adding item to cart should produce a new invoice
         current_cart.add_to_cart(self.PROD_2, 1)
         invoice_2 = InvoiceController.for_cart(current_cart.cart)
         self.assertNotEqual(invoice_1.invoice, invoice_2.invoice)
+
+        # The old invoice should automatically be voided
+        invoice_1_new = rego.Invoice.objects.get(pk=invoice_1.invoice.id)
+        invoice_2_new = rego.Invoice.objects.get(pk=invoice_2.invoice.id)
+        self.assertTrue(invoice_1_new.void)
+        self.assertFalse(invoice_2_new.void)
+
         # Invoice should have two line items
         line_items = rego.LineItem.objects.filter(invoice=invoice_2.invoice)
         self.assertEqual(2, len(line_items))
@@ -104,3 +110,25 @@ class InvoiceTestCase(RegistrationCartTestCase):
         self.assertEqual(
             self.PROD_1.price * Decimal("0.5"),
             invoice_1.invoice.value)
+
+    def test_invoice_voids_self_if_cart_is_invalid(self):
+        current_cart = CartController.for_user(self.USER_1)
+
+        # Should be able to create an invoice after the product is added
+        current_cart.add_to_cart(self.PROD_1, 1)
+        invoice_1 = InvoiceController.for_cart(current_cart.cart)
+
+        self.assertFalse(invoice_1.invoice.void)
+
+        # Adding item to cart should produce a new invoice
+        current_cart.add_to_cart(self.PROD_2, 1)
+        invoice_2 = InvoiceController.for_cart(current_cart.cart)
+        self.assertNotEqual(invoice_1.invoice, invoice_2.invoice)
+
+        # Viewing invoice_1's invoice should show it as void
+        invoice_1_new = InvoiceController(invoice_1.invoice)
+        self.assertTrue(invoice_1.invoice.void)
+
+        # Viewing invoice_2's invoice should *not* show it as void
+        invoice_2_new = InvoiceController(invoice_2.invoice)
+        self.assertFalse(invoice_2.invoice.void)