def test_shift():
""" Test shift """
l = DoubleLinkedList()
with pytest.raises(LookupError):
l.shift()
for i in range(1, 4):
l.append(i)
assert l._size == 3
assert l.shift() == 3
assert l.head.value == 1
assert l.tail.value == 2
assert l._size == 2
assert l.shift() == 2
assert l.head.value == 1
assert l.tail.value == 1
assert l._size == 1
def test_shift():
""" Test shift """
l = DoubleLinkedList()
with pytest.raises(LookupError):
l.shift()
for i in range(1,4):
l.append(i)
assert l._size == 3
assert l.shift() == 3
assert l.head.value == 1
assert l.tail.value == 2
assert l._size == 2
assert l.shift() == 2
assert l.head.value == 1
assert l.tail.value == 1
assert l._size == 1
class Queue(object):
'''Stack is a composition of LinkedList'''
def __init__(self, input=None):
self.queue = DoubleLinkedList(input)
def enqueue(self, val):
self.queue.insert(val)
def dequeue(self):
shift_val = self.queue.shift()
return shift_val
def size(self):
return self.queue._size()
def peek(self):
return self.queue.tail.data
class Deque(object):
'''Deque is a composition of Double Linked List'''
def __init__(self, input=None):
'''create doubly linked list'''
self.deque = DoubleLinkedList(input)
def append(self, val):
self.deque.append(val)
def append_left(self, val):
self.deque.insert(val)
def pop(self):
return self.deque.pop()
def pop_left(self):
return self.deque.shift()
def peek(self):
try:
return self.deque.head.data
except AttributeError:
return None
def peek_left(self):
try:
return self.deque.tail.data
except AttributeError:
return None
def size(self):
size = 0
current_spot = self.deque.head
while current_spot:
size += 1
current_spot = current_spot.toward_tail
return size
class Deque(object):
'''Deque is a composition of Double Linked List'''
def __init__(self, input=None):
'''create doubly linked list'''
self.deque = DoubleLinkedList(input)
def append(self, val):
self.deque.append(val)
def append_left(self, val):
self.deque.insert(val)
def pop(self):
return self.deque.pop()
def pop_left(self):
return self.deque.shift()
def peek(self):
try:
return self.deque.head.data
except AttributeError:
return None
def peek_left(self):
try:
return self.deque.tail.data
except AttributeError:
return None
def size(self):
size = 0
current_spot = self.deque.head
while current_spot:
size += 1
current_spot = current_spot.toward_tail
return size
def test_shift():
from double_linked import DoubleLinkedList
new_list = DoubleLinkedList(LIST_INPUT)
assert new_list.shift() == 6
def test_empty_double_linked():
from double_linked import DoubleLinkedList
new_list = DoubleLinkedList()
new_list.insert(999)
assert new_list.shift() == 999
def test_shift():
from double_linked import DoubleLinkedList
new_list = DoubleLinkedList(LIST_INPUT)
assert new_list.shift() == 6
def test_empty_double_linked():
from double_linked import DoubleLinkedList
new_list = DoubleLinkedList()
new_list.insert(999)
assert new_list.shift() == 999
