60 lines
1.8 KiB
Python
60 lines
1.8 KiB
Python
import unittest
|
|
|
|
|
|
################################################################################
|
|
# Solution
|
|
################################################################################
|
|
def delete_node(x):
|
|
if not x.next:
|
|
raise Exception('Cannot delete the last node in a linked list.')
|
|
else:
|
|
x.value = x.next.value
|
|
x.next = x.next.next
|
|
|
|
|
|
################################################################################
|
|
# Tests
|
|
################################################################################
|
|
class Test(unittest.TestCase):
|
|
class LinkedListNode(object):
|
|
def __init__(self, value, next=None):
|
|
self.value = value
|
|
self.next = next
|
|
|
|
def get_values(self):
|
|
node = self
|
|
values = []
|
|
while node is not None:
|
|
values.append(node.value)
|
|
node = node.next
|
|
return values
|
|
|
|
def setUp(self):
|
|
self.fourth = Test.LinkedListNode(4)
|
|
self.third = Test.LinkedListNode(3, self.fourth)
|
|
self.second = Test.LinkedListNode(2, self.third)
|
|
self.first = Test.LinkedListNode(1, self.second)
|
|
|
|
def test_node_at_beginning(self):
|
|
delete_node(self.first)
|
|
actual = self.first.get_values()
|
|
expected = [2, 3, 4]
|
|
self.assertEqual(actual, expected)
|
|
|
|
def test_node_in_middle(self):
|
|
delete_node(self.second)
|
|
actual = self.first.get_values()
|
|
expected = [1, 3, 4]
|
|
self.assertEqual(actual, expected)
|
|
|
|
def test_node_at_end(self):
|
|
with self.assertRaises(Exception):
|
|
delete_node(self.fourth)
|
|
|
|
def test_one_node_in_list(self):
|
|
unique = Test.LinkedListNode(1)
|
|
with self.assertRaises(Exception):
|
|
delete_node(unique)
|
|
|
|
|
|
unittest.main(verbosity=2)
|