def test_node_constructor_one_diection():
"""Test that there is a node that points at another node one direction."""
from dll import Node
n = Node(0, Node(1))
assert n.val == 0
assert isinstance(n.nxt, Node)
assert n.prev is None
def test_4(self):
""" test that tail.next returns none """
dl = DoubleLinkedList()
n1 = Node(5)
n2 = Node(3)
dl.append(n1)
dl.append(n2)
self.assertEqual(dl.tail._next, None)
def test_node_constructor_both_diections():
"""Test that there is a node that points at two different nodes."""
from dll import Node
n = Node(0, Node(1), Node(2))
assert n.val == 0
assert isinstance(n.nxt, Node)
assert isinstance(n.prev, Node)
assert n.nxt is not n.prev
def test_2(self):
""" test append by head """
dl = DoubleLinkedList()
n1 = Node(5)
n2 = Node(3)
dl.append(n1)
dl.append(n2)
self.assertEqual(dl.head._next._value, 3)
def test_3(self):
""" test append by tail """
dl = DoubleLinkedList()
n1 = Node(5)
n2 = Node(3)
dl.append(n1)
dl.append(n2)
self.assertEqual(dl.tail._value, 3)
def test_4(self):
"""check that head is still the first node added to list"""
n1 = Node('A')
n2 = Node('B')
dl = DoubleLinkedList()
dl.append(n1)
dl.append(n2)
self.assertEqual(dl.head._value, 'A')
def test_3(self):
"""add two nodes. test that 2nd append makes changes tail to new node"""
n1 = Node('A')
n2 = Node('B')
dl = DoubleLinkedList()
dl.append(n1)
dl.append(n2)
self.assertEqual(dl.tail._value, 'B')
def test_6(self):
""" prev of prior head is now node 2 (n1 here) """
dl = DoubleLinkedList()
n1 = Node(5)
n2 = Node(3)
dl.push(n1)
dl.push(n2)
self.assertEqual(n1._prev._value, 3)
def test_5(self):
""" added node is now head """
dl = DoubleLinkedList()
n1 = Node(5)
n2 = Node(3)
dl.push(n1)
dl.push(n2)
self.assertEqual(dl.head._value, 3)
def test_7(self):
""" next of prior head is now head """
dl = DoubleLinkedList()
n1 = Node(5)
n2 = Node(3)
dl.push(n1)
dl.push(n2)
dl.pop()
self.assertEqual(dl.head._value, 5)
def test_8(self):
""" prev of prior tail is now tail """
dl = DoubleLinkedList()
n1 = Node(5)
n2 = Node(3)
dl.push(n1)
dl.push(n2)
dl.shift()
self.assertEqual(dl.tail._value, 3)
def test_6(self):
"""check that pop removes head"""
n1 = Node('A')
n2 = Node('B')
dl = DoubleLinkedList()
dl.append(n1) #head and tail at this point
dl.append(n2) # A is head and B is now tail
dl.pop() # removes A so head value should be B
self.assertEqual(dl.head._value, 'B')
def test_5(self):
"""check that push adds to front"""
n1 = Node('A')
n2 = Node('B')
dl = DoubleLinkedList()
dl.append(n1)
dl.append(n2)
n3 = Node('C') #will push C to front(head)
dl.push(n3)
self.assertEqual(dl.head._value, 'C')
def test_9(self):
""" remove by value, removed node's next now next of removed node's prev """
dl = DoubleLinkedList()
n1 = Node(5)
n2 = Node(3)
n3 = Node(6)
dl.append(n1)
dl.append(n2)
dl.append(n3)
dl.remove(3)
self.assertEqual(dl.head._next._value, 6)
def test_7(self):
"""check that shift removes last node"""
n1 = Node('A')
n2 = Node('B')
n3 = Node('C')
dl = DoubleLinkedList()
dl.append(n1)
dl.append(n2)
dl.append(n3)
dl.shift()
self.assertEqual(dl.tail._value, 'B')
def test_10(self):
""" remove by value, return an exception if doesn't exist """
dl = DoubleLinkedList()
n1 = Node(5)
n2 = Node(3)
n3 = Node(6)
dl.append(n1)
dl.append(n2)
dl.append(n3)
dl.remove(7)
self.assertEqual(dl.remove(7), "Node does not exist!")
def test_node_init():
"""Test node class init."""
from dll import Node
new_node = Node(0, None, None)
assert new_node.contents == 0
assert new_node.next_node is None
assert new_node.previous_node is None
def test_node_constructor_with_no_nxt():
"""Test that there is a node that points at None."""
from dll import Node
n = Node(0)
assert n.val == 0
assert n.nxt is None
assert n.prev is None
def test_8(self):
"""test to remove tail by using remove method"""
n1 = Node('A')
n2 = Node('B')
n3 = Node('C')
dl = DoubleLinkedList()
dl.append(n1)
dl.append(n2)
dl.append(n3)
dl.remove('C') #this removes C so tail should become BaseException
self.assertEqual(dl.tail._value, 'B')
def test_delete(self):
n = 5
for i in range(n):
self.dll.append(i)
# Delete existing value
node = self.dll.find(2)
prev = node.prev
next = node.next
val = self.dll.delete(node)
self.assertEqual(2, val, "Returned value should be 2")
self.assertEqual(n - 1, len(self.dll),
"Length should be " + str(n - 1))
self.assertIsNone(self.dll.find(2),
"There should be no value of 2 in the dll")
self.assertEqual(next, prev.next, "Links previous to next node")
self.assertEqual(prev, next.prev, "Links next node to previous")
# Delete non existing value
node = Node(2)
val = self.dll.delete(node)
self.assertIsNone(val, "Should return None")
self.assertEqual(n - 1, len(self.dll),
"Length should still be " + str(n - 1))
# print(self.dll)
# Delete first node
node = self.dll.find(0)
next = node.next
self.dll.delete(node)
self.assertEqual(len(self.dll), n - 2,
"Length should be " + str(n - 2))
self.assertIsNone(self.dll.find(0),
"There should be no value of 0 in the dll")
for elem in self.dll:
self.assertEqual(next.value, elem,
"Next should now be at the HEAD")
break
def sortedInsert(dll, data):
newNode = Node(data)
if dll.head and newNode.data < dll.head.data:
newNode.next = dll.head
newNode.next.prev = newNode
dll.head = newNode
return
current = dll.head
while current and current.next:
if current.next.data > newNode.data:
break
current = current.next
if current is None:
dll.head = newNode
elif current.next is None:
current.next = newNode
newNode.prev = current
dll.tail = newNode
else:
newNode.next = current.next
newNode.prev = current
newNode.next.prev = newNode
current.next = newNode
def test_test_previous_node():
"""Test whether creating a previous with another previous node."""
test_node2 = Node(10)
test_node1 = Node(20, previous_node=test_node2)
assert test_node1.previous_node.value == 10
def test_test_next_node():
"""Test whether creating a next with another node."""
test_node1 = Node(15)
test_node2 = Node(10, next_node=test_node1)
assert test_node2.next_node.value == 15
def test_create_empty_node():
"""Test whether we create a node with a value 'val'."""
test_node = Node()
assert test_node.value is None
def test_create_node():
"""Test whether we create a node with a value 'val'."""
test_node = Node(15)
assert test_node.value == 15
def test_node():
"""Assert node class is created with specified val."""
from dll import Node
new_node = Node(4)
assert new_node.val == 4
def test_1(self):
"""make a node"""
n1 = Node('A')
self.assertEqual(n1._value, 'A')
def test_init_empty_node():
"""Test a new empty node is None."""
from dll import Node
new_node = Node()
assert new_node.value is None
def test_1(self):
n1 = Node(5)
self.assertEqual(n1.value(), 5)
def test_init_node():
"""Test a new node with value has correct value."""
from dll import Node
new_node = Node(5)
assert new_node.value == 5