Fix debug code challenge (#4632)

tests/challenges/debug_code/data/code.py

@@ -2,18 +2,12 @@
 from typing import List, Optional
 
 
-def two_sum(nums: List, target: int) -> Optional[int]:
+def two_sum(nums: List, target: int) -> Optional[List[int]]:
     seen = {}
     for i, num in enumerate(nums):
+        typo
         complement = target - num
         if complement in seen:
             return [seen[complement], i]
         seen[num] = i
     return None
-
-
-# Example usage:
-nums = [2, 7, 11, 15]
-target = 9
-result = two_sum(nums, target)
-print(result)  # Output: [0, 1]

tests/challenges/debug_code/data/test.py

@@ -0,0 +1,31 @@
+# mypy: ignore-errors
+from code import two_sum
+from typing import List
+
+
+def test_two_sum(nums: List, target: int, expected_result: List[int]) -> None:
+    result = two_sum(nums, target)
+    print(result)
+    assert (
+        result == expected_result
+    ), f"AssertionError: Expected the output to be {expected_result}"
+
+
+if __name__ == "__main__":
+    # test the trivial case with the first two numbers
+    nums = [2, 7, 11, 15]
+    target = 9
+    expected_result = [0, 1]
+    test_two_sum(nums, target, expected_result)
+
+    # test for ability to use zero and the same number twice
+    nums = [2, 7, 0, 15, 12, 0]
+    target = 0
+    expected_result = [2, 5]
+    test_two_sum(nums, target, expected_result)
+
+    # test for first and last index usage and negative numbers
+    nums = [-6, 7, 11, 4]
+    target = -2
+    expected_result = [0, 3]
+    test_two_sum(nums, target, expected_result)

tests/challenges/debug_code/data/two_sum_tests.py

@@ -1,30 +0,0 @@
-# mypy: ignore-errors
-# we need a new line at the top of the file to avoid a syntax error
-
-
-def test_two_sum(nums, target, expected_result):
-    # These tests are appended to the two_sum file so we can ignore this error for now
-    result = two_sum(nums, target)
-    print(result)
-    assert (
-        result == expected_result
-    ), f"AssertionError: Expected the output to be {expected_result}"
-
-
-# test the trivial case with the first two numbers
-nums = [2, 7, 11, 15]
-target = 9
-expected_result = [0, 1]
-test_two_sum(nums, target, expected_result)
-
-# test for ability to use zero and the same number twice
-nums = [2, 7, 0, 15, 12, 0]
-target = 0
-expected_result = [2, 5]
-test_two_sum(nums, target, expected_result)
-
-# test for first and last index usage and negative numbers
-nums = [-6, 7, 11, 4]
-target = -2
-expected_result = [0, 3]
-test_two_sum(nums, target, expected_result)