def test_sorted():
lst = [2, 3, 5, 7, 11, 13]
merge_sort(lst)
assert lst == [2, 3, 5, 7, 11, 13]
def test_list_reverse_order():
lst = [42, 23, 16, 15, 8, 4]
merge_sort(lst)
assert lst == [4, 8, 15, 16, 23, 42]
def test_nearly_sorted():
lst = [2, 3, 5, 7, 13, 11]
merge_sort(lst)
assert lst == [2, 3, 5, 7, 11, 13]
def test_simple_lst():
lst = [8, 4, 23, 42, 16, 15]
merge_sort(lst)
assert lst == [4, 8, 15, 16, 23, 42]
def test_few_uniques():
lst = [5, 12, 7, 5, 5, 7]
merge_sort(lst)
assert lst == [5, 5, 5, 7, 7, 12]
def test_list_zeros_and_negative():
lst = [-23, -0.5, -4, 0, -1]
merge_sort(lst)
assert lst == [-23, -4, -1, -0.5, 0]
def test_list_reverse_order2():
lst = [20, 18, 12, 8, 5, -2]
merge_sort(lst)
assert lst == [-2, 5, 8, 12, 18, 20]