def test_dll_remove():
"""Test for dll remove."""
from dll import DoublyLinkedList
one_dll, empty_dll, new_dll = sample_dll()
new_dll.remove(3)
assert new_dll.length == 4
assert new_dll.head_node.next_node.next_node.contents == 2
assert new_dll.head_node.next_node.next_node.previous_node.contents == 4
try:
new_dll.remove(10)
except NameError:
assert True
new_dll.remove(5)
assert new_dll.head_node.contents == 4
new_dll.remove(1)
assert new_dll.tail_node.contents == 2
empty_dll = DoublyLinkedList()
try:
empty_dll.remove(100)
except NameError:
assert True
one_dll = DoublyLinkedList([1])
one_dll.remove(1)
assert one_dll.head_node is None
assert one_dll.tail_node is None
assert one_dll.length == 0
class Queue(object):
"""Queue class. Startrek. Nerds."""
def __init__(self):
"""Init the Queue."""
self.container = DoublyLinkedList()
def enqueue(self, val):
"""Insert into front position."""
self.container.insert(val)
def dequeue(self, val):
"""Remove item in the list."""
self.container.remove(val)
def peek(self):
"""Check the next node in the queue."""
if self.container.tail is None:
return None
return self.container.tail.previous.val
def size(self):
"""Return size of container."""
current = self.container.head
counter = 1
if current is None:
return 0
while current.next is not None:
counter += 1
current = current.next
return counter
def test_remove():
"""Test if selected Node is removed from list."""
from dll import DoublyLinkedList
my_list = DoublyLinkedList()
my_list.insert('last')
my_list.insert('second')
my_list.insert('head')
my_list.remove('second')
assert my_list.head.next.val == 'last'
def test_DLL_rm(mk_dll):
zeroth = DoublyLinkedList()
with pytest.raises(IndexError):
zeroth.remove(3)
populated = mk_dll
# Remove from the head
assert populated.head.data == 0
populated.remove(0)
assert populated.head.data == 1
# Remove from the tail
assert populated.tail.data == 19
populated.remove(19)
assert populated.tail.data == 18
# Remove from the middle
current = populated.head
for a in range(5):
current = current.next
the_nexts_value = current.next.data
populated.remove(the_nexts_value)
assert the_nexts_value + 1 == current.next.data
# Try to remove a value that isn't there
with pytest.raises(ValueError):
populated.remove('not there')
def test_remove_empty():
"""Assert remove works on empty list."""
from dll import DoublyLinkedList
my_list = DoublyLinkedList()
with pytest.raises(AttributeError):
my_list.remove('chicken')