import unittest;

class Test(unittest.TestCase):
     def test_longest_word(self):
            sentence = "This is Andela"
            self.assertEqual('Andela', longest(sentence))

     def test_one_word(self):
            sentence = "This"
            self.assertEqual("This", longest(sentence))

def longest(word_list):
   longest_word = ''
   longest_size = 0
    for word in word_list:
        if len(word) > longest_size:
            longest_word = word
            longest_size = len(word)
    return longest_word


words = ("This is Andela")
word_list = words.split()
longest(word_list)