Contributes to TheAlgorithms#9943 by adding tests to monotonic_array.py

Addeded doctest in the if __name__. Checks for negaitves and an array of same integers

data_structures/arrays/monotonic_array.py

@@ -9,6 +9,16 @@ def is_monotonic(nums: list[int]) -> bool:
  True
  >>> is_monotonic([1, 3, 2])
  False
+ >>> is_monotonic([1,2,3,4,5,6,5])
+ False
+ >>> is_monotonic([-3,-2,-1])
+ True
+ >>> is_monotonic([-5,-6,-7])
+ True
+ >>> is_monotonic([0,0,0])
+ True
+ >>> is_monotonic([-100,0,100])
+ True
  """
  return all(nums[i] <= nums[i + 1] for i in range(len(nums) - 1)) or all(
  nums[i] >= nums[i + 1] for i in range(len(nums) - 1)
@@ -21,3 +31,6 @@ def is_monotonic(nums: list[int]) -> bool:
  print(is_monotonic([1, 2, 2, 3])) # Output: True
  print(is_monotonic([6, 5, 4, 4])) # Output: True
  print(is_monotonic([1, 3, 2])) # Output: False
+
+ import doctest
+ doctest.testmod()