class Queue:
"""
Queue using Circular Double Linked List
"""
def __init__(self):
self.queue = LinkedList()
self.is_full = False
self.is_empty = True
def __len__(self):
return len(self.queue)
def enqueue(self, key, data=None):
"""
add an item to the queue
:param key: key to add
:param data: new node data
"""
self.queue.insert_end(key, data)
def dequeue(self):
"""
remove an item from the queue
:return: item key
"""
node = self.queue.fild_last_node()
self.queue.remove_beginning()
if self.queue.head is None:
self.is_empty = True
else:
self.is_empty = False
if node is None:
return None
return node.key
def peek(self):
"""
gets the element at the front of the queue without removing it
:return: item key
"""
node = self.queue.head
if node is None:
return None
return node.key
def test_remove_beginning(self):
"""
test remove_beginning()
"""
# test on empty linked list
list1 = LinkedList()
list1.remove_beginning()
# generate linked list
nums = 10
list1, reference_arr = generate_filled_list(LinkedList, nums)
# remove from beginning
list1.remove_beginning()
list_arr = list(list1)
# compare results to reference
reference_arr = reference_arr[1:]
self.assertEqual(list_arr, reference_arr)