def test_remove_duplicates():
middle = linkednode.LinkedNode(10)
middle += 30
middle += 40
middle += 50
middle += 50
middle += 50
middle += 50
middle += 60
middle = linkednode_exercises.remove_duplicates(middle)
assert linkednode.print_list(middle) == '10, 30, 40, 50, 60'
beginning = linkednode.LinkedNode(10)
beginning += 10
beginning += 10
beginning += 10
beginning += 20
beginning += 30
beginning = linkednode_exercises.remove_duplicates(beginning)
assert linkednode.print_list(beginning) == '10, 20, 30'
ending = linkednode.LinkedNode(10)
ending += 20
ending += 30
ending += 30
ending = linkednode_exercises.remove_duplicates(beginning)
assert linkednode.print_list(ending) == '10, 20, 30'
jumpy = linkednode.LinkedNode(1)
jumpy += 2
jumpy += 1
jumpy += 2
jumpy += 3
jumpy += 1
jumpy = linkednode_exercises.remove_duplicates(jumpy)
assert linkednode.print_list(jumpy) == '1, 2, 3'
mess = linkednode.LinkedNode(10)
mess += 10
mess += 10
mess += 20
mess += 30
mess += 30
mess += 40
mess += 50
mess += 10
mess += 60
mess += 60
mess += 30
mess = linkednode_exercises.remove_duplicates(mess)
assert linkednode.print_list(mess) == '10, 20, 30, 40, 50, 60'
def test_insert():
list = LinkedNode(10)
list += 30
list += 40
list += 50
assert repr(list) == '10'
assert repr(list.next_node.key) == '30'
assert print_list(list) == '10, 30, 40, 50'
def test_delete():
list = LinkedNode(10)
list += 20
list += 30
list += 40
list = delete_item(list, 30)
assert print_list(list) == '10, 20, 40'
list = delete_item(list, 10)
assert print_list(list) == '20, 40'
list = delete_item(list, 50)
assert print_list(list) == '20, 40'
list = delete_item(list, 40)
assert print_list(list) == '20'
list = delete_item(list, 20)
assert type(list) == NoneType