book-store: updates tests to v1.4.0 (exercism#1478)

thomasjpfan · cmccandless · commit ebfbbf77b653 · 2018-08-23T09:11:26.000-04:00
* book-store: updates tests to v1.4.0

* FIX: Updates example
diff --git a/exercises/book-store/book_store_test.py b/exercises/book-store/book_store_test.py
@@ -3,7 +3,7 @@
 from book_store import calculate_total
 
 
-# Tests adapted from `problem-specifications//canonical-data.json` @ v1.3.0
+# Tests adapted from `problem-specifications//canonical-data.json` @ v1.4.0
 
 class BookStoreTest(unittest.TestCase):
     def test_only_a_single_book(self):
@@ -30,6 +30,9 @@ def test_five_different_books(self):
     def test_two_groups_of_4_is_cheaper_than_group_of_5_plus_group_of_3(self):
         self.assertEqual(calculate_total([1, 1, 2, 2, 3, 3, 4, 5]), 5120)
 
+    def test_two_groups_of_4_is_cheaper_than_groups_of_5_and_3(self):
+        self.assertEqual(calculate_total([1, 1, 2, 3, 4, 4, 5, 5]), 5120)
+
     def test_group_of_4_plus_group_of_2_is_cheaper_than_2_groups_of_3(self):
         self.assertEqual(calculate_total([1, 1, 2, 2, 3, 4]), 4080)
 
diff --git a/exercises/book-store/example.py b/exercises/book-store/example.py
@@ -1,3 +1,4 @@
+from collections import Counter
 BOOK_PRICE = 800
 
 
@@ -12,12 +13,16 @@ def calculate_total(books, price_so_far=0.):
     if not books:
         return price_so_far
 
-    groups = list(set(books))
+    reordered_books = []
+    groups = []
+    for value, count in Counter(books).most_common():
+        reordered_books = reordered_books + [value] * count
+        groups.append(value)
     min_price = float('inf')
 
     for i in range(len(groups)):
 
-        remaining_books = books[:]
+        remaining_books = reordered_books[:]
 
         for v in groups[:i + 1]:
             remaining_books.remove(v)
