Merge pull request #4 from kejbaly2/good_luck

A few improvements and suggestions - thanks :)

.gitignore

@@ -1,6 +1,10 @@
+# vim swap files
+*.sw*
+
 *.py[cod]
 
 # C extensions
+*.c
 *.so
 
 # Packages
@@ -33,4 +37,7 @@ nosetests.xml
 # Mr Developer
 .mr.developer.cfg
 .project
-.pydevproject
+ .pydevproject
+
+# Rope
+.ropeproject/

okfncart/cart.py

@@ -3,41 +3,39 @@
 #
 from . import getproducts
 
+
 class Cart(object):
 
-    def __init__(self, products, offers=None):
-        self._contents = {}
-        self._products = products
-        self._discounts = {}
-        if not offers:
-            self._offers=[]
-        else:
-            self._offers= offers
+    def __init__(self, products=None, offers=None):
+        # products can be added after instance init
+        # products must be available in _products before they can be
+        # added to the cart!
+        self.contents = {}  # holds cart content quantities
+        self._products = products or {}  # 'universe' of available products
+        self._discounts = {}  # discounts that have been applied to the cart
+        self._offers = offers or []  # 'universe' offers that can be applied
 
     def load_products(self, filename):
-        self._products = getproducts.loadproducts(filename)
-
-    @property
-    def contents(self):
-        return self._contents
+        self._products.update(getproducts.loadproducts(filename))
 
     def add(self, product, quantity):
-        # initialize the product in the basket, this could also be done
-        # with a collection.defaultdict
-        if product not in self._contents:
-            self._contents[product] = 0
-        self._contents[product] += quantity
+        # product being added must be available in the available
+        # _products 'universe'
+        assert product in self._products
+        # initialize the product in the basket
+        self.contents.setdefault(product, 0)
+        self.contents[product] += quantity
 
     def _add_discount(self, name, price):
         self._discounts[name] = price
 
     def get_price(self):
         price = 0.0
-        for content in self.contents.items():
-            price += self._products[content[0]] * content[1]
-        self._discounts = {}
+        for product, qty in self.contents.items():
+            price += self._products[product] * qty
         for offer in self._offers:
+            # pass in the this cart to the discount class
             offer.add_discount(self)
-        for discount in self._discounts.items():
-            price += discount[1]
+        for discount in self._discounts.values():
+            price += discount
         return price

okfncart/test_main.py

@@ -44,11 +44,24 @@ def test_cartobjject_loadproducts(self):
         here = os.path.abspath(os.path.dirname(__file__))
         file_name = os.path.join(here, 'tests', 'products.csv')
         prods = getproducts.loadproducts(file_name)
-        my_cart = cart.Cart(None)
-        self.assertEqual(my_cart._products, None)
+        my_cart = cart.Cart()
+        self.assertEqual(my_cart._products, {})
         my_cart.load_products(file_name)
         self.assertEqual(my_cart._products,prods)
 
+    def test_cartobjject_bulk_contents_update(self):
+        # loadproducts should update, not override products
+        # passed in on init
+        here = os.path.abspath(os.path.dirname(__file__))
+        file_name = os.path.join(here, 'tests', 'products.csv')
+        prods1 = {'item': 0.1}
+        prods2 = getproducts.loadproducts(file_name)
+        prods_all = prods1.copy()
+        prods_all.update(prods2)
+        my_cart = cart.Cart(products=prods1)
+        self.assertEqual(my_cart._products, prods1)
+        my_cart.load_products(file_name)
+        self.assertEqual(my_cart._products, prods_all)
 
 
 class BasicCartTestCase(unittest.TestCase):
@@ -73,6 +86,21 @@ def test_add_to_cart(self):
         my_cart.add('apple', 5)
         self.assertEqual(my_cart.contents['apple'], 8)
 
+    def test_add_invalid_to_cart(self):
+        """
+        check that we can't add an invalid product to the cart
+        """
+        products =  {'snickers bar': 0.7, 'strawberries': 2.0,
+                    'apple': 0.15, 'ice cream': 3.49}
+        my_cart = cart.Cart(products)
+
+        # this should work
+        my_cart.add('apple', 1)
+
+        # but this should raise AssertionError
+        with self.assertRaises(AssertionError):
+            my_cart.add('invalid_product', 1)
+
     def test_compute_cart_value(self):
         """
         calculate the total cost of the cart
@@ -175,6 +203,36 @@ def test_20pc_off_snickers_4_mars(self):
         self.assertEqual(my_cart.contents['snickers'], 2)
         self.assertEqual(my_cart.get_price(),2.6)
 
+    def test_multiple_discounts(self):
+        # changed the price of all products to 1.0 to simplify
+        products = {'snickers': 1.0, 'strawberries': 1.0, 'mars': 1.0}
+        my_cart_no_offers = cart.Cart(products)
+        my_cart_no_offers.add('mars', 1)
+        my_cart_no_offers.add('snickers', 1)
+        # should be 2.00 with no offers
+        self.assertEqual(my_cart_no_offers.get_price(), 2.0)
+
+        offer1 = offers.OfferP1p2XpcOff('mars', 'snickers', 0.2)
+        offer2 = offers.OfferB2g3rdf('strawberries')
+        my_cart_offers_1 = cart.Cart(products, [offer1])
+        my_cart_offers_2 = cart.Cart(products, [offer2])
+        my_cart_offers_both = cart.Cart(products, [offer1, offer2])
+
+        my_cart_offers_1.add('mars', 1)
+        my_cart_offers_1.add('snickers', 1)
+        # should get 0.20 off
+        self.assertEqual(my_cart_offers_1.get_price(), 1.8)
+
+        my_cart_offers_2.add('strawberries', 3)
+        # should get 1.00 off (3 strawberries @ 1.00 - 1 strawberry @ 1.00)
+        self.assertEqual(my_cart_offers_2.get_price(), 2.0)
+
+        my_cart_offers_both.add('mars', 1)
+        my_cart_offers_both.add('snickers', 1)
+        my_cart_offers_both.add('strawberries', 3)
+        # should get 0.20 off + 1.00 off (1.20)
+        self.assertEqual(my_cart_offers_both.get_price(), 3.8)
+
 
 def test_suite():
     suite = unittest.TestSuite()