Add test cases for max subarray (#53)

sols/python/code_challenges/arrays/two_pointers.py

@@ -8,16 +8,6 @@ class MaxSubarrayDivideAndConquer:
     def cross_sum(self, nums: List[int], low: int, high: int, mid: int) -> int:
         """Compute the maximum sum of a subarray passing through the middle.
 
-        Input: nums = [5,4,-1,7,8]
-        Output: 23
-
-        Input: nums = [1]
-        Output: 1
-
-        Input: nums = [-2,1,-3,4,-1,2,1,-5,4]
-        Output: 6
-        Explanation: [4,-1,2,1] has the largest sum = 6.
-
         This is ``O(n)`` in complexity.
 
         :param nums: List of numbers
@@ -72,7 +62,7 @@ def divide_and_conquer(self, nums: List[int], low: int, high: int) -> int:
         cross_sum = self.cross_sum(nums, low, high, mid)
         return max(left_sum, right_sum, cross_sum)
 
-    def maxSubArray(self, nums: List[int]) -> int:
+    def max_sub_array(self, nums: List[int]) -> int:
         """Implement a divide and conquer solution.
 
         This algorithm is ``O(nlog(n))`` and it is based on the idea of

sols/python/tests/arrays/test_two_pointers.py

@@ -1,5 +1,10 @@
 """Test cases for two_pointers."""
-from code_challenges.arrays.two_pointers import rotate_naive, rotate_mem_opt
+from code_challenges.arrays.two_pointers import (
+    rotate_naive,
+    rotate_mem_opt,
+    MaxSubarrayDivideAndConquer,
+    max_sub_array_sum,
+)
 
 
 def test_sample_cases():
@@ -48,3 +53,27 @@ def test_360_and_k_rotation():
     k = len(nums) + 3
     rotate_mem_opt(nums, k)
     assert nums == [5, 6, 7, 1, 2, 3, 4]
+
+
+def test_max_subarray_sum():
+    """Simple test cases for max subarray sum."""
+    nums = [5, 4, -1, 7, 8]
+    assert (
+        MaxSubarrayDivideAndConquer().max_sub_array(nums)
+        == 23
+        == max_sub_array_sum(nums)
+    )
+
+    nums = [-2, 1, -3, 4, -1, 2, 1, -5, 4]
+    assert (
+        MaxSubarrayDivideAndConquer().max_sub_array(nums)
+        == 6
+        == max_sub_array_sum(nums)
+    )
+
+    nums = [1]
+    assert (
+        MaxSubarrayDivideAndConquer().max_sub_array(nums)
+        == 1
+        == max_sub_array_sum(nums)
+    )