class LinkedList_Test_Operations_On_List_with_1000_Random_Elements(unittest.TestCase):
def setUp(self):
self._linked_list = LinkedList()
self._shadow_list = []
for i in range(10):
random_element = randint(0, 1000)
self._linked_list.append(random_element)
self._shadow_list.append(random_element)#will keep track of count and index
def test_count_index_remove_index_count_on_each_removal(self):
"""
Check count, index before and after each predictable removal operation
"""
for i in self._shadow_list[:]:
self.assertEqual(self._linked_list.length, len(self._shadow_list))
self.assertEqual(self._linked_list.index(i), self._shadow_list.index(i))
self._shadow_list.remove(i)
self._linked_list.remove(i)
try:
self._shadow_list.index(i)
self.assertEqual(self._linked_list.index(i), self._shadow_list.index(i))
except ValueError:
self.assertEqual(self._linked_list.index(i), -1)
self.assertEqual(self._linked_list.length, len(self._shadow_list))
class LinkedList_Test_Insert_At_Index_In_Middle_With_4_Elements(unittest.TestCase):
def setUp(self):
self._linkedList = LinkedList()
self._linkedList.append(1)
self._linkedList.append(2)
self._linkedList.append(4)
self._linkedList.append(5)
def test_insert_at_negative_index_of_empty_list(self):
expected_length = self._linkedList.length + 1
element_to_insert = 3
insert_at_index = 2
self._linkedList.insert_at(insert_at_index, element_to_insert)# list will become 1, 2, 3, 4, 5
self.assertEqual(self._linkedList.length, expected_length, 'Linked list length did not tally after insert in the middle')
self.assertEqual(self._linkedList.index(3), insert_at_index, 'index of new element is not where we insert it at!')
#iterate and check
expected_list = []
for element in self._linkedList:
expected_list.append(element)
self.assertEqual(expected_list, [1, 2, 3, 4, 5], 'List was not same as expected after insert At index')
def tearDown(self):
self._linkedList = None
class LinkedList_Test_Check_Head_On_Remove_In_4_Element_List(unittest.TestCase):
def setUp(self):
self._linkedList = LinkedList()
self._linkedList.append(1)
self._linkedList.append(2)
self._linkedList.append(3)
self._linkedList.append(4)
def test_tail_node_on_remove(self):
#list is [1, 2, 3, 4]
self._linkedList.remove(3)#removed head. Head must be same node
self.assertEqual(self._linkedList.head, 1)
#Now list is [1, 2, 4]
self._linkedList.remove(1)#head should next be 2
self.assertEqual(self._linkedList.head, 2, 'head must be adjusted on deletion of first node')
#Now list is [2, 4]
self._linkedList.remove(2)#head should next be 4
self.assertEqual(self._linkedList.head, 4, 'head must be adjusted on deletion of first node')
#Now list is [4]
self._linkedList.remove(4)#head should next be None
self.assertEqual(self._linkedList.head, None, 'Head must be None on empty list')
def tearDown(self):
self._linkedList = None
class LinkedList_Test_get_item_With_1_Elements(unittest.TestCase):
def setUp(self):
self._linkedList = LinkedList()
def test_reverse_iteration_of_1_element_list(self):
element_to_add = 1
self._linkedList.append(element_to_add)
self.assertEqual(self._linkedList[0], element_to_add, 'list get item did not yield expected item')
self.assertEqual(self._linkedList[-1], element_to_add, 'list get item did not yield expected item')
self.assertEqual(self._linkedList[10], element_to_add, 'list get item did not yield expected item')
def tearDown(self):
self._linkedList = None
class LinkedList_Test_Count_With_4_Predictable_Elements(unittest.TestCase):
def setUp(self):
self._linkedList = LinkedList()
self._linkedList.append(1)
self._linkedList.append(2)
self._linkedList.append(3)
self._linkedList.append(4)
def test_count_of_list(self):
self.assertEqual(self._linkedList.length, 4, 'Empty List length must be 4')
def tearDown(self):
self._linkedList = None
class LinkedListHashBucket(collections.MutableMapping):
'''
A hash bucket is used to hold objects that 'hash to the same value' (collision) in a hash table.
This is hash a bucket using a LIST. This masquerades as a python dict in code where it is used.
Note: HASHBUCKET ITERATION YIELDS KEYS. not the key value pairs in the bucket.
'''
def __init__(self):
self._list_of_kv_pairs = LinkedList() #we use our linked list!
def __len__(self):
'''
The number of entries in the bucket!
'''
return self._list_of_kv_pairs.length
def get(self, key, default = None):
'''
Get object associated with a key and on key miss return specified default. This is there in
Python dict and this class masquerades as dict, so we implement it.
'''
try:
value = self[key]
return value
except KeyError:
return default
def __getitem__(self, key):
for kv_pair in self._list_of_kv_pairs:
if kv_pair.key == key:
return kv_pair.value
raise KeyError('Key Error: %s ' % repr(key))
def __delitem__(self, key):
for kv_pair in self._list_of_kv_pairs:
if kv_pair.key == key:
self._list_of_kv_pairs.remove(kv_pair)
return
raise KeyError('Key Error: %s ' % repr(key))
def __setitem__(self, key, obj):
for kv_pair in self._list_of_kv_pairs:
if kv_pair.key == key:
kv_pair.value = obj
return
self._list_of_kv_pairs.append(KeyValuePair(key = key, value = obj))
def __iter__(self):
for kvpair in self._list_of_kv_pairs:
yield kvpair.key
class LinkedList_Test_Remove_Middle_Element_From_4_Element_List(unittest.TestCase):
def setUp(self):
self._linkedList = LinkedList()
self._linkedList.append(1)
self._linkedList.append(2)
self._linkedList.append(3)
self._linkedList.append(4)
def test_count_of_list(self):
self._linkedList.remove(3)
self.assertEqual(self._linkedList.length, 3, 'Length not valid after trying to remove non-existin element')
def tearDown(self):
self._linkedList = None
class LinkedList_Test_Reverse_Iteration_With_1_Elements(unittest.TestCase):
def setUp(self):
self._linkedList = LinkedList()
self._linkedList.append(1)
def test_reverse_iteration_of_1_element_list(self):
expected_reverse_iter_list = [1]
reverse_iter_of_list = []
for element in reversed(self._linkedList):
reverse_iter_of_list.append(element)
self.assertEqual(reverse_iter_of_list, expected_reverse_iter_list, 'reverse iteration did not yield expected list')
def tearDown(self):
self._linkedList = None
class LinkedList_Test_IndexOf_Elements_In_4_Element_List(unittest.TestCase):
def setUp(self):
self._linkedList = LinkedList()
self._linkedList.append(1)
self._linkedList.append(2)
self._linkedList.append(3)
self._linkedList.append(4)
def test_index(self):
for element in range(1, 5):
index = self._linkedList.index(element)
self.assertEqual(index + 1, element, 'index failed for element')
def tearDown(self):
self._linkedList = None
class LinkedList_Test_Insert_At_Index_Larger_Than_Length_With_4_Elements(unittest.TestCase):
def setUp(self):
self._linkedList = LinkedList()
self._linkedList.append(1)
self._linkedList.append(2)
self._linkedList.append(3)
self._linkedList.append(4)
def test_insert_at_negative_index_of_empty_list(self):
expected_length = self._linkedList.length + 1
element_to_insert = 20
self._linkedList.insert_at(100, element_to_insert)
self.assertEqual(self._linkedList.length, expected_length, 'Linked list length did not tally after insert at huge index')
self.assertEqual(self._linkedList.tail, element_to_insert, 'Linked list tail must be same as new element inserted at huge index')
self.assertEqual(self._linkedList.index(20), expected_length - 1, 'index of new element did not add up')
def tearDown(self):
self._linkedList = None
class LinkedList_Test_Remove_Duplicates_With_2_Identical_Elements(unittest.TestCase):
def setUp(self):
self._linkedList = LinkedList()
element_to_append = 1
self._linkedList.append(element_to_append)
self._linkedList.append(element_to_append)
def test_remove_duplicates_of_list_with_2_identical_elements(self):
old_head = self._linkedList.head
expected_tail = old_head
self._linkedList.remove_duplicates()
expected_length = 1
self.assertEqual(self._linkedList.length, expected_length, 'Linked list length did not add up after removing duplicates')
self.assertEqual(self._linkedList.head, old_head, 'Linked list head did not add up after removing duplicates')
self.assertEqual(self._linkedList.tail, expected_tail, 'Linked list tail did not add up after removing duplicates')
def tearDown(self):
self._linkedList = None
class LinkedList_Test_Remove_Duplicates_With_Duplicates_At_Middle(unittest.TestCase):
def setUp(self):
#build [2, 1, 1, 1, 3]
self._linkedList = LinkedList()
self._linkedList.append(2)
element_to_append = 1
self._linkedList.extend([element_to_append, element_to_append, element_to_append])
self._linkedList.append(3)
def test_remove_duplicates_of_list_with_2_duplicates_in_Middle(self):
expected_head = self._linkedList._head
expected_tail = self._linkedList._tail
self._linkedList.remove_duplicates()
expected_length = 3
self.assertEqual(self._linkedList.length, expected_length, 'Linked list length did not add up after removing duplicates')
self.assertEqual(self._linkedList._head, expected_head, 'Linked list head did not add up after removing duplicates')
self.assertEqual(self._linkedList._tail, expected_tail, 'Linked list tail did not add up after removing duplicates')
def tearDown(self):
self._linkedList = None
class LinkedList_Test_Remove_Duplicates_With_Duplicates_At_Tail(unittest.TestCase):
def setUp(self):
#build [2, 1, 1, 1]
self._linkedList = LinkedList()
self._linkedList.append(2)
element_to_append = 1
self._linkedList.extend([element_to_append, element_to_append, element_to_append])
def test_remove_duplicates_of_list_with_2_identical_elements(self):
expected_head = self._linkedList._head
expected_tail = self._linkedList._head.next_node
self._linkedList.remove_duplicates()
expected_length = 2
#compare references of head and tail
self.assertEqual(self._linkedList.length, expected_length, 'Linked list length did not add up after removing duplicates')
self.assertEqual(self._linkedList._head, expected_head, 'Linked list head did not add up after removing duplicates')
self.assertEqual(self._linkedList._tail, expected_tail, 'Linked list tail did not add up after removing duplicates')
def tearDown(self):
self._linkedList = None
class LinkedList_Test_Check_Tail_On_Remove_In_4_Element_List(unittest.TestCase):
def setUp(self):
self._linkedList = LinkedList()
self._linkedList.append(1)
self._linkedList.append(2)
self._linkedList.append(3)
self._linkedList.append(4)
def test_tail_node_on_remove(self):
self._linkedList.remove(1)#removed head. Tail must be same node
self.assertEqual(self._linkedList.tail, 4)
#Now list is [2, 3, 4]
self._linkedList.remove(4)#tail should next be 3
self.assertEqual(self._linkedList.tail, 3, 'Tail must be adjusted on deletion of last node')
#Now list is [2, 3]
self._linkedList.remove(2)#tail should next be 3
self.assertEqual(self._linkedList.tail, 3, 'Tail must be adjusted on deletion of last node')
#Now list is [3]
self._linkedList.remove(3)#tail should next be None
self.assertEqual(self._linkedList.tail, None, 'Tail must be None on empty list')
def tearDown(self):
self._linkedList = None
class LinkedList_Test_extend_With_Predictable_Elements(unittest.TestCase):
'''
Test the extend operation of singly_linked_list.
a) Create 2 lists.
b) Add the second list to the end of the first list.
c) Check the indices of the newly added elements.
'''
def setUp(self):
self._linkedList = LinkedList()
self._linkedList.append(1)
self._linkedList.append(2)
self._linkedList.append(3)
self._linkedList.append(4)
#create a second linkedlist with 5, 6, 7
self._secondList = LinkedList()
self._secondList.append(5)
self._secondList.append(6)
self._secondList.append(7)
def test_extend_of_list(self):
self.assertEqual(self._linkedList.length, 4, 'Original list before extend must be 4')
count_before_extend = self._linkedList.length
next_index_will_be = count_before_extend
self._linkedList.extend(self._secondList)
#check new length
self.assertEqual(self._linkedList.length, count_before_extend + self._secondList.length, 'New length after extend must add up.')
#check if the elements of shadow list are present
for element in self._secondList:
self.assertEqual(self._linkedList.index(element), next_index_will_be
, 'Indices of new elements after extend must add up')
next_index_will_be += 1
def tearDown(self):
self._linkedList = None
self._secondList = None
def print_reverse_list(link_list):
elements_in_list = []
#iterate over the list
for element in reversed(link_list):
elements_in_list.append(element)
print('Reversed List is now %s' % elements_in_list)
#length of the list
print('Length of the list is %s' % len(link_list))
if __name__ == '__main__':
link_list = LinkedList()
#add one element
print('Adding element 1 to list')
link_list.append(1)
#we add the following list (iterable) of elements
print('Adding elements 2 ,3 , 4, 5, 6, 7, 8, 9, 10')
elements = [2, 3, 4, 5, 6, 7, 8, 9, 10]
link_list.extend(elements)
#head
print('Head of list is: %s' % str(link_list.head))
#tail
print('Tail of list is: %s' % str(link_list.tail))
print('Print list by iterating')
#Find an element's index
element = 4