def test_length(self):
"""
Tests that the correct length of the list is
returned.
"""
sll = SinglyLinkedList()
sll.add_to_head(1)
sll.add_to_head(2)
sll.add_to_head(3)
length = len(sll)
self.assertEqual(length, 3)
def test_remove_from_head(self):
"""
Tests that Node has been removed from the
head of the list.
"""
sll = SinglyLinkedList()
sll.add_to_head(1)
sll.add_to_head(2)
self.assertEqual(sll.head.value, 2)
sll.remove_from_head()
self.assertEqual(sll.head.value, 1)
self.assertEqual(len(sll), 1)
def test_add_to_head(self):
"""
Tests that a new Node has been added to the
head of the list.
"""
sll = SinglyLinkedList()
sll.add_to_head(1)
sll.add_to_head(2)
self.assertEqual(sll.head.value, 2)
sll.add_to_head(3)
self.assertEqual(sll.head.value, 3)
self.assertEqual(len(sll), 3)
class Stack:
def __init__(self):
self.size = 0
# Why is our DLL a good choice to store our elements?
self.storage = SinglyLinkedList()
def push(self, value):
self.storage.add_to_head(value)
self.size += 1
def pop(self):
if self.size:
self.size -= 1
return self.storage.remove_from_head()
return None
def len(self):
return self.size
# pass
class Stack:
def __init__(self):
self.size = 0
self.storage = SinglyLinkedList()
def __len__(self):
return self.size
def push(self, value):
# increase the size of the stack by one
self.size += 1
# add an element to the front of the linked list
self.storage.add_to_head(value)
def pop(self):
# check if empty
if self.size == 0:
return None
# decrement the size of the stack by one
self.size -= 1
# remove the first element in storage and return the removed head
node = self.storage.remove_head()
return node
def test_get_max(self):
"""
Tests that the maximum value in the list is
returned.
"""
sll = SinglyLinkedList()
sll.add_to_head(3)
sll.add_to_tail(9)
sll.add_to_head(10)
sll.add_to_head(4)
max_val = sll.get_max()
self.assertEqual(max_val, 10)
def test_move_to_front(self):
"""
Tests that a Node has been moved to the front
of the list.
"""
sll = SinglyLinkedList()
sll.add_to_head(1)
sll.add_to_head("testing")
node = sll.head
sll.add_to_head(5)
sll.move_to_front(node)
self.assertEqual(sll.head.value, "testing")
self.assertEqual(len(sll), 3)
def test_move_to_end(self):
"""
Tests that a Node has been moved to the end of
the list.
"""
def get_tail_val(list):
currentNode = list.head
while currentNode.next:
currentNode = currentNode.next
return currentNode.value
sll = SinglyLinkedList()
sll.add_to_head(1)
sll.add_to_head(2)
sll.add_to_head("testing")
node = sll.head
sll.add_to_head(3)
sll.move_to_end(node)
self.assertEqual(get_tail_val(sll), "testing")
self.assertEqual(len(sll), 4)
def test_delete(self):
"""
Tests that a Node has been deleted from the
list.
"""
def search_for_val(list, val):
currentNode = list.head
found_val = None
while currentNode.next:
if currentNode.value == val:
found_val = currentNode.value
currentNode = currentNode.next
return found_val
sll = SinglyLinkedList()
sll.add_to_head(1)
sll.add_to_head(2)
sll.add_to_head(3)
sll.add_to_head(4)
sll.add_to_head(5)
node = sll.head
sll.add_to_head(6)
sll.add_to_head(7)
sll.add_to_head(8)
sll.add_to_head(9)
sll.add_to_head(10)
sll.delete(node)
self.assertEqual(search_for_val(sll, node.value), None)
def test_remove_from_tail(self):
"""
Tests that a Node has been removed from the
tail of the list.
"""
def get_tail_val(list):
currentNode = list.head
while currentNode.next:
currentNode = currentNode.next
return currentNode.value
sll = SinglyLinkedList()
sll.add_to_head(1)
sll.add_to_head(2)
sll.add_to_head(3)
sll.add_to_head(4)
sll.add_to_head(5)
sll.add_to_head(6)
sll.add_to_head(7)
sll.add_to_head(8)
sll.add_to_head(9)
sll.add_to_head(10)
sll.remove_from_tail()
self.assertEqual(get_tail_val(sll), 2)
self.assertEqual(len(sll), 9)
