Create counting list

Define a function create_counting_list that receives a number to count up
to. Normally because you know the number of loops you would want to use a for
loop but in this case we will use a while loop to emulate a for loop. Return
a list where each element counts up to the number provided starting from 0. If
the number provided to count to is negative, return 'cannot be negative'.

Examples:

>>> create_counting_list(7)
[1, 2, 3, 4, 5, 6, 7]
>>> create_counting_list(3)
[1, 2, 3]
>>> create_counting_list(0)
[]
>>> create_counting_list(-1)
'cannot be negative'
import unittest


class CreateCountingListTestCase(unittest.TestCase):

    def test_count_to_7(self):
        self.assertEqual(create_counting_list(7), [1, 2, 3, 4, 5, 6, 7])

    def test_count_to_3(self):
        self.assertEqual(create_counting_list(3), [1, 2, 3])

    def test_do_not_count(self):
        self.assertEqual(create_counting_list(0), [])

    def test_negative(self):
        self.assertEqual(create_counting_list(-1), 'cannot be negative')