Add function to generate unique validation code for gift cards.

api/src/shop/gift_card_util.py

@@ -0,0 +1,14 @@
+from secrets import token_hex
+
+
+def generate_gift_card_code(length=16):
+    """
+    Generate a unique validation code for gift cards.
+
+    Parameters:
+    - length: The length of the validation code (default is 16).
+
+    Returns:
+    A unique validation code.
+    """
+    return token_hex(length)[:length].upper()

api/src/shop/test/gift_card_test.py

@@ -0,0 +1,20 @@
+from unittest import TestCase
+from shop.gift_card_util import generate_gift_card_code
+
+
+class GiftCardTest(TestCase):
+    def test_generate_validation_code_default_length(self):
+        validation_code = generate_gift_card_code()
+        msg = "Test failed: validation code is not 16 characters long."
+        self.assertEqual(len(validation_code), 16, msg=msg)
+
+    def test_generate_validation_code_custom_length(self):
+        validation_code = generate_gift_card_code(32)
+        msg = "Test failed: validation code is not 32 characters long."
+        self.assertEqual(len(validation_code), 32, msg=msg)
+
+    def test_generate_validation_code_unique(self):
+        validation_code_1 = generate_gift_card_code()
+        validation_code_2 = generate_gift_card_code()
+        msg = "Test failed: validation codes are not unique."
+        self.assertNotEqual(validation_code_1, validation_code_2, msg=msg)