def test_sorting():
"""Test sorting for various test cases."""
print ('in test_sorting')
assert b([1, 2, 3, 4]) == [1, 2, 3, 4]
assert b([1, 4, 3, 2]) == [1, 2, 3, 4]
assert b([9, 9, 8, 9]) == [8, 9, 9, 9]
def test_sort_reversed():
"""Test that sorting works on reverse-sorted data."""
print ('in test_sort_reversed')
data = [1, 2, 3, 4, 5]
reverse = data[::-1]
assert b(reverse) == data
def test_sort_allequal():
"""Test that sorting handles data with identical elements."""
print ('in test_sort_allequal')
data = [1, 1, 1, 1, 1]
rel = [1, 1, 1, 1, 1]
assert b(data) == rel
def test_sort_sorted():
"""Test that sorting works on sorted data."""
print ('in test_sort_sorted')
sort = [1, 2, 3, 4, 5]
rel = [1, 2, 3, 4, 5]
assert b(sort) == rel
def test_original_unchanged():
"""Test that sorting leaves the original data unchanged."""
print ('in test_original_unchanged')
original = [3, 6, 5]
real = [3, 6, 5]
assert b(real) is not original
def test_sorted_is_not_original():
"""Test that the sorting function returns a new object."""
print ('in test_sorted_is_not_original')
test = [1, 2, 3]
copy = test
assert b(test) is not copy
def test_single():
"""Test that the sorting function works for single-element list"""
print ('in test_single')
assert b([1]) == [1]
def test_empty():
"""Test that the sorting function works for empty list"""
print ('in test_empty')
assert b([]) == []