def test_five():
test = 'aBcD e'
expected = 'e DcBa'
actual = reverse_string(test)
assert actual == expected, 'Error on test_five.'
def test_four():
test = 'a '
expected = ' a'
actual = reverse_string(test)
assert actual == expected, 'Error on test_four.'
def test_one():
test = 'bunny'
expected = 'ynnub'
actual = reverse_string(test)
assert actual == expected, 'Error on test_one.'
def test_two():
test = 'the dog is sleeping'
expected = 'gnipeels si god eht'
actual = reverse_string(test)
assert actual == expected, 'Error on test_two.'