def test_insertanddelete100fromhead():
L = LinkedList()
for i in range(100):
x = ListElement(i)
L.LIST_INSERT(x)
for i in range(100):
assert L.head.key == 99 - i
L.LIST_DELETE(L.head)
assert L.head == None
def test_insertanddelete100fromtail():
L = LinkedList()
z = ListElement(0)
L.LIST_INSERT(z)
for i in range(1, 100):
x = ListElement(i)
L.LIST_INSERT(x)
for i in range(100):
assert z.key == i
L.LIST_DELETE(z)
z = z.prev
assert L.head == None
def test_delete():
L = LinkedList()
x = ListElement(0)
L.LIST_INSERT(x)
y = ListElement(1)
L.LIST_INSERT(y)
z = ListElement(2)
L.LIST_INSERT(z)
assert z.next == y
assert y.prev == z
assert y.next == x
assert x.prev == y
L.LIST_DELETE(y)
assert z.next == x
assert x.prev == z
def test_insertanddelete():
L = LinkedList()
x = ListElement(0)
L.LIST_INSERT(x)
L.LIST_DELETE(x)
assert L.head == None
