Updated the checkout session manager with new methods

oscar/apps/checkout/utils.py

             del self.request.session[self.SESSION_KEY][namespace][key]
             self.request.session.modified = True
 
+    def _flush_namespace(self, namespace):
+        self.request.session[self.SESSION_KEY][namespace] = {}
+        self.request.session.modified = True
+
     def flush(self):
         """
         Delete session key
     def get_guest_email(self):
         return self._get('guest', 'email')
 
-    # Shipping addresses
+    # Shipping address
+    # ================
+    # Options:
+    # 1. No shipping required (eg digital products)
+    # 2. Ship to new address (entered in a form)
+    # 3. Ship to an addressbook address (address chosen from list)
 
     def reset_shipping_data(self):
-        self._unset('shipping', 'not_required')
-        self._unset('shipping', 'new_address_fields')
-        self._unset('shipping', 'user_address_id')
+        self._flush_namespace('shipping')
 
     def no_shipping_required(self):
         """
         """
         return self._get('shipping', 'new_address_fields')
 
-    def user_address_id(self):
+    def shipping_user_address_id(self):
         """
         Get user address id from session
         """
         return self._get('shipping', 'user_address_id')
+    user_address_id = shipping_user_address_id
 
     def is_shipping_required(self):
         return self._get('shipping', 'is_required', True)
         has_old_address = self.user_address_id() > 0
         return has_new_address or has_old_address
 
-    # Shipping methods
+    # Shipping method
+    # ===============
 
     def use_free_shipping(self):
         """
         return bool(self._get('shipping', 'method_code'))
 
     # Billing address fields
+    # ======================
+    #
+    # There are 3 common options:
+    # 1. Billing address is entered manually through a form
+    # 2. Billing address is selected from address book
+    # 3. Billing address is the same as the shipping address
 
     def bill_to_new_address(self, address_fields):
         """
         Store address fields for a billing address.
         """
+        self._flush_namespace('billing')
         self._set('billing', 'new_address_fields', address_fields)
 
-    def new_billing_address_fields(self):
+    def bill_to_user_address(self, address):
         """
-        Return fields for a billing address
+        Set an address from a user's address book as the billing address
+
+        :address: The address object
         """
-        return self._get('billing', 'new_address_fields')
+        self._flush_namespace('billing')
+        self._set('billing', 'user_address_id', address.id)
 
-    def billing_address_same_as_shipping(self):
+    def bill_to_shipping_address(self):
         """
         Record fact that the billing address is to be the same as
         the shipping address.
         """
-        self._set('payment', 'billing_address_same_as_shipping', True)
+        self._flush_namespace('billing')
+        self._set('billing', 'billing_address_same_as_shipping', True)
+
+    # Legacy method name
+    billing_address_same_as_shipping = bill_to_shipping_address
 
     def is_billing_address_same_as_shipping(self):
-        return self._get('payment', 'billing_address_same_as_shipping', False)
+        return self._get('billing', 'billing_address_same_as_shipping', False)
+
+    def billing_user_address_id(self):
+        """
+        Return the ID of the user address being used for billing
+        """
+        return self._get('billing', 'user_address_id')
+
+    def new_billing_address_fields(self):
+        """
+        Return fields for a billing address
+        """
+        return self._get('billing', 'new_address_fields')
 
     # Payment methods
+    # ===============
 
     def pay_by(self, method):
         self._set('payment', 'method', method)

tests/unit/checkout_tests.py

+from django.test import TestCase
+from django.test.client import RequestFactory
+from django.contrib.sessions.middleware import SessionMiddleware
+import mock
+
+from oscar.apps.checkout.utils import CheckoutSessionData
+
+
+class TestCheckoutSession(TestCase):
+    """
+    oscar.apps.checkout.utils.CheckoutSessionData
+    """
+
+    def setUp(self):
+        request = RequestFactory().get('/')
+        SessionMiddleware().process_request(request)
+        self.session_data = CheckoutSessionData(request)
+
+    def test_allows_data_to_be_written_and_read_out(self):
+        self.session_data._set('namespace', 'key', 'value')
+        self.assertEqual('value', self.session_data._get('namespace', 'key'))
+
+    def test_allows_set_data_can_be_unset(self):
+        self.session_data._set('namespace', 'key', 'value')
+        self.session_data._unset('namespace', 'key')
+        self.assertIsNone(self.session_data._get('namespace', 'key'))
+
+    def test_stores_guest_email(self):
+        self.session_data.set_guest_email('a@a.com')
+        self.assertEquals('a@a.com', self.session_data.get_guest_email())
+
+    def test_allows_a_namespace_to_be_flushed(self):
+        self.session_data._set('ns', 'a', 1)
+        self.session_data._set('ns', 'b', 2)
+        self.session_data._flush_namespace('ns')
+        self.assertIsNone(self.session_data._get('ns', 'a'))
+        self.assertIsNone(self.session_data._get('ns', 'b'))
+
+    def test_allows_bill_to_user_address(self):
+        address = mock.Mock()
+        address.id = 1
+        self.session_data.bill_to_user_address(address)
+        self.assertEqual(1, self.session_data.billing_user_address_id())