def test_pop_non_empty():
"""Assert first node gets removed and returned."""
from dll import DoublyLinkedList
my_list = DoublyLinkedList()
my_list.insert(4)
my_list.insert(5)
assert my_list.pop() == 5
def test_pop_single_item_list():
"""Test pop on single item list."""
from dll import DoublyLinkedList
my_list = DoublyLinkedList()
my_list.insert(4)
my_list.pop()
assert my_list.head is None
def test_insert_on_non_emtpy_list():
"""Assert insert on non-empty list works."""
from dll import DoublyLinkedList
my_list = DoublyLinkedList()
my_list.insert(4)
my_list.insert('Diana')
assert my_list.head.val == 'Diana'
def test_append_non_empty():
"""Assert node gets appended to the end of the lsit."""
from dll import DoublyLinkedList
my_list = DoublyLinkedList()
my_list.insert(4)
my_list.append(8)
assert my_list.tail.val == 8
def test_assert_previous():
"""Assert second node points to its previous."""
from dll import DoublyLinkedList
my_list = DoublyLinkedList()
my_list.insert('Daniel')
my_list.insert('Diana')
assert my_list.head.val == 'Diana'
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_shift():
"""Assert shift works on non empty list."""
from dll import DoublyLinkedList
my_list = DoublyLinkedList()
my_list.insert(1)
my_list.insert(2)
my_list.insert(3)
assert my_list.shift() == 1
def test_tail():
"""Assert the last node is the tail."""
from dll import DoublyLinkedList
my_list = DoublyLinkedList()
my_list.insert(4)
my_list.insert(5)
my_list.insert(6)
assert my_list.tail.val == 4
class Deque(object):
"""Deque class."""
def __init__(self):
"""Initilizer of deque class."""
self.container = DoublyLinkedList()
def append_left(self, val):
"""Append val to the head of the list."""
self.container.insert(val)
def append(self, val):
"""Append val to the tail of the list."""
self.container.append(val)
def pop(self):
"""Return and remove head from the list."""
self.container.shift()
def pop_left(self):
"""Remove head of deque and return that value."""
self.container.pop()
def peek(self):
"""Check the next node in the deque."""
if self.container.tail is None:
return None
return self.container.tail.val
def peek_left(self):
"""Return the tail of the deque."""
if self.container.head is None:
return None
return self.container.head.val
def size(self):
"""Return the size of the deque."""
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
class Deque(object):
"""Deque class."""
def __init__(self):
"""Initilizer of deque class."""
self.container = DoublyLinkedList()
def append_left(self, val):
"""Append val to the head of the list."""
self.container.insert(val)
def append(self, val):
"""Append val to the tail of the list."""
self.container.append(val)
def pop(self):
"""Return and remove head from the list."""
self.container.shift()
def pop_left(self):
"""Remove head of deque and return that value."""
self.container.pop()
def peek(self):
"""Check the next node in the deque."""
if self.container.tail is None:
return None
return self.container.tail.val
def peek_left(self):
"""Return the tail of the deque."""
if self.container.head is None:
return None
return self.container.head.val
def size(self):
"""Return the size of the deque."""
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_ins():
dbl = DoublyLinkedList()
# First case with an empty list
dbl.insert('insert')
assert dbl.head.data == 'insert'
assert dbl.tail.data == 'insert'
assert dbl.head.next is None
assert dbl.head.prev is None
assert dbl.tail.next is None
assert dbl.tail.next is None
dbl.insert('next')
assert dbl.head.data == 'next'
# Test for updating of prev in in the second item
assert dbl.head.next.prev.data == 'next'
assert dbl.tail.data == 'insert'
dbl.insert('final')
assert dbl.head.data == 'final'
assert dbl.head.next.prev.data == 'final'
assert dbl.tail.data == 'insert'
def test_insert_on_empty_list():
"""Assert insert works."""
from dll import DoublyLinkedList
my_list = DoublyLinkedList()
my_list.insert(4)
assert my_list.head.val == 4