import unittest

def binary_search(target, data):

data.sort()

start = 0

end = len(data) - 1

while start <= end:

mid = (start + end) // 2

if data[mid] == target:

return mid

elif data[mid] < target:

start = mid + 1

else:

end = mid - 1

return None

class BinarySearchTest(unittest.TestCase):

def test_binary_search(self):

self.assertEqual(

binary_search(4, [1, 2, 3, 4, 5]), 3

)

self.assertEqual(

binary_search(4, [5, 4, 3, 2, 1]), 3

)

self.assertEqual(

binary_search(5, [5, 4, 3, 2, 1]), 4

)

self.assertEqual(

binary_search(1, [5, 4, 3, 2, 1]), 0

)

self.assertEqual(

binary_search(6, [1, 2, 3, 4, 5]), None

)

self.assertEqual(

binary_search(0, [5, 4, 3, 2, -1]), None

)

if __name__ == '__main__':

unittest.main()