book-store: Add test checking that solutions can mix groups of 4 and 5

exercises/book-store/book_store_test.py

@@ -2,7 +2,7 @@
 
 from book_store import total
 
-# Tests adapted from `problem-specifications//canonical-data.json` @ v1.4.0
+# Tests adapted from `problem-specifications//canonical-data.json` @ v1.5.0
 
 
 class BookStoreTest(unittest.TestCase):
@@ -83,6 +83,16 @@ def test_four_groups_of_four_are_cheaper_than_two_groups_each_of_five_and_three(
         table = 10240
         self.assertEqual(total(results), table)
 
+    def test_two_groups_of_four_and_a_group_of_five(self):
+        results = [1, 1, 1, 2, 2, 2, 3, 3, 3, 4, 4, 5, 5]
+        table = 8120
+        self.assertEqual(total(results), table)
+
+    def test_shuffled_book_order(self):
+        results = [1, 2, 3, 4, 5, 1, 2, 3, 4, 5, 1, 2, 3]
+        table = 8120
+        self.assertEqual(total(results), table)
+
 
 if __name__ == "__main__":
     unittest.main()

exercises/book-store/example.py

@@ -47,5 +47,6 @@ def step(basket, book):
 def total(basket):
     if len(basket) == 0:
         return 0
+    basket = sorted(basket)
     start = Grouping([{basket[0]}])
     return round(min(reduce(step, basket[1:], [start])).total())