def test_flatten(self):
"""
Flatten makes 2d list list into 1d. Here we are checking if it worked (so every element is str not list).
"""
testing_list = [["list 1"], ["list 2"]]
result_list = flatten(testing_list)
for item in result_list:
self.assertTrue(isinstance(item, str))
def test_flatten_result(self):
"""
Make sure flatten returns the right number of items
"""
testing_list = [["list 1", "list 1"], ["list 2"]]
result_list = flatten(testing_list)
self.assertTrue(len(result_list) == 3)