def test_pop_empty(self):
dll = LinkedList()
assert dll.head is None
assert dll.tail is None
assert dll.size == 0
with pytest.raises(IndexError):
dll.pop()
def test_util_sublist_start_greater_than_end(self):
with pytest.raises(IndexError):
items = 10
dll = LinkedList()
for i in range(items):
dll.push(i)
sublist(dll, 3, 2)
def test_pop_2nd_negative(self):
dll = LinkedList()
items = 100
assert dll.head is None
assert dll.tail is None
assert dll.size == 0
for i in range(items - 1, -1, -1):
assert dll.push(i) is None
assert isinstance(dll.head, Node)
assert isinstance(dll.head.next, Node)
assert dll.head.prev is None
assert isinstance(dll.tail, Node)
assert isinstance(dll.tail.prev, Node)
assert dll.tail.next is None
assert dll.size == items
for j in range(items - 2, 0, -1):
second = dll.pop(-2)
assert isinstance(second, Node)
assert second.next is None
assert second.prev is None
assert second.data == j
assert isinstance(dll.head, Node)
assert isinstance(dll.head.next, Node)
assert dll.head.prev is None
assert isinstance(dll.tail, Node)
assert isinstance(dll.tail.prev, Node)
assert dll.tail.next is None
assert dll.head.data == 0
assert dll.tail.data == items - 1
assert dll.size == 2
def test_pop_tails_negative(self):
dll = LinkedList()
items = 100
assert dll.head is None
assert dll.tail is None
assert dll.size == 0
for i in range(items - 1, -1, -1):
assert dll.push(i) is None
assert isinstance(dll.head, Node)
assert isinstance(dll.head.next, Node)
assert dll.head.prev is None
assert isinstance(dll.tail, Node)
assert isinstance(dll.tail.prev, Node)
assert dll.tail.next is None
assert dll.size == items
for j in range(items - 1, -1, -1):
assert isinstance(dll.tail, Node)
tail = dll.pop(-1)
assert isinstance(tail, Node)
assert tail.data == j
assert tail.next == None
assert dll.size == items - (items - j)
assert dll.head is None
assert dll.tail is None
assert dll.size == 0
def test_is_empty_2(self):
dll = LinkedList()
assert dll.head is None
assert dll.tail is None
assert dll.size == 0
assert dll.append(1) is None
assert dll.is_empty() is False
def test_insert_empty(self):
dll = LinkedList()
assert dll.is_empty()
assert dll.insert(0, 0) is None
assert isinstance(dll.head, Node)
assert isinstance(dll.tail, Node)
assert dll.head is dll.tail
assert dll.size == 1
def test_remove_tail(self):
dll = LinkedList()
items = 2
assert dll.is_empty()
for i in range(items):
assert dll.append(i) is None
assert dll.size == items
assert dll.tail is not dll.head
assert dll.remove(1) is None
assert dll.head is dll.tail
assert dll.size == items - 1
def test_append_empty(self):
dll = LinkedList()
assert dll.head is None
assert dll.tail is None
assert dll.size == 0
assert dll.append(1) is None
assert isinstance(dll.head, Node)
assert isinstance(dll.tail, Node)
assert dll.head.data == dll.tail.data
assert dll.head is dll.tail
assert dll.size == 1
def test_pop_out_of_range_negative(self):
dll = LinkedList()
assert dll.head is None
assert dll.tail is None
assert dll.size == 0
assert dll.push(1) is None
assert isinstance(dll.head, Node)
assert isinstance(dll.tail, Node)
assert dll.size == 1
with pytest.raises(IndexError):
dll.pop(-2)
def test_clear(self):
dll = LinkedList()
items = 100
assert dll.is_empty()
for i in range(items):
assert dll.append(i) is None
assert isinstance(dll.head, Node)
assert isinstance(dll.tail, Node)
assert dll.size == items
assert dll.clear() is None
assert dll.head is None
assert dll.tail is None
assert dll.size == 0
def test_reverse(self):
dll = LinkedList()
items = 100
assert dll.is_empty()
assert dll.reverse() is None
assert dll.is_empty()
for i in range(items):
assert dll.append(i) is None
assert isinstance(dll.head, Node)
assert isinstance(dll.tail, Node)
assert dll.size == items
assert dll.head is not dll.tail
assert dll.head.data == 0
assert dll.head.prev is None
assert dll.tail.data == items - 1
assert dll.tail.next is None
assert dll.reverse() is None
assert isinstance(dll.head, Node)
assert isinstance(dll.tail, Node)
assert dll.size == items
assert dll.head is not dll.tail
assert dll.head.data == items - 1
assert dll.head.prev is None
assert dll.tail.data == 0
assert dll.tail.next is None
match = items - 1
for node in dll:
assert node.data == match
match -= 1
assert dll.reverse() is None
match = 0
for node in dll:
assert node.data == match
match += 1
def test_extend_iterable_object(self):
items = 100
first = LinkedList()
second = list(range(items))
assert first.is_empty()
assert first.extend(second) is None
assert isinstance(first.head, Node)
assert isinstance(first.tail, Node)
assert first.head is not first.tail
assert first.size == len(second)
match = 0
for node in first:
assert node.data == match
match += 1
def test_iter(self):
dll = LinkedList()
items = 10
counter = 0
assert dll.head is None
assert dll.tail is None
assert dll.size == 0
for i in range(items):
assert dll.append(i) is None
assert isinstance(dll.head, Node)
assert isinstance(dll.tail, Node)
assert dll.size == items
for node in dll:
assert isinstance(node, Node)
assert isinstance(node.data, int)
counter += 1
assert counter == items
def test_remove_mid(self):
dll = LinkedList()
items = 3
assert dll.is_empty()
for i in range(items):
assert dll.append(i) is None
assert dll.size == items
assert dll.head is not dll.tail
assert dll.remove(1) is None
assert dll.head is not dll.tail
assert dll.head.data == 0
assert dll.tail.data == 2
assert dll.head.next is dll.tail
assert dll.tail.prev is dll.head
assert dll.head.prev is None
assert dll.tail.next is None
assert dll.size == items - 1
def test_remove_not_found(self):
dll = LinkedList()
assert dll.is_empty() is True
assert dll.push(1) is None
assert dll.is_empty() is False
with pytest.raises(ValueError):
dll.remove(2)
def test_sublist(self):
dll = LinkedList()
items = 10
start, end = 0, 3
assert dll.head is None
assert dll.size == 0
for i in range(items):
assert dll.push(i) is None
assert type(dll.head) is Node
assert dll.size == 10
sl = sublist(dll, start, end)
assert type(sl) is LinkedList
assert type(sl.head) is Node
assert sl.size == (end - start)
compare = items - 1
for node in sl:
assert node.data == compare
compare -= 1
def test_insert_new_tail(self):
dll = LinkedList()
assert dll.is_empty()
assert dll.push(1) is None
assert isinstance(dll.head, Node)
assert isinstance(dll.tail, Node)
assert dll.head is dll.tail
assert dll.size == 1
assert dll.insert(1, 2) is None
assert isinstance(dll.head, Node)
assert isinstance(dll.tail, Node)
assert dll.head is not dll.tail
assert dll.head.data == 1
assert dll.tail.data == 2
assert dll.head.next is dll.tail
assert dll.head.prev is None
assert dll.tail.prev is dll.head
assert dll.tail.next is None
assert dll.size == 2
def test_insert_new_head_negative_out_of_bounds(self):
dll = LinkedList()
assert dll.is_empty()
assert dll.push(1) is None
assert isinstance(dll.head, Node)
assert isinstance(dll.tail, Node)
assert dll.head is dll.tail
assert dll.size == 1
assert dll.insert(-1000, 2) is None
assert isinstance(dll.head, Node)
assert isinstance(dll.tail, Node)
assert dll.head is not dll.tail
assert dll.head.data == 2
assert dll.tail.data == 1
assert dll.head.next is dll.tail
assert dll.head.prev is None
assert dll.tail.prev is dll.head
assert dll.tail.next is None
assert dll.size == 2
def test_append_multiple(self):
dll = LinkedList()
items = 100
assert dll.head is None
assert dll.tail is None
assert dll.size == 0
for i in range(items):
assert dll.append(i) is None
assert dll.size == i + 1
assert dll.tail.data == i
assert isinstance(dll.head, Node)
assert isinstance(dll.tail, Node)
assert dll.head is not dll.tail
assert dll.size == items
for j in range(items):
assert dll.pop().data == j
assert dll.head is None
assert dll.tail is None
assert dll.size == 0
def test_push_multiple(self):
dll = LinkedList()
items = 100
assert dll.head is None
assert dll.tail is None
assert dll.size == 0
for i in range(items):
assert dll.push(i) is None
assert isinstance(dll.head, Node)
assert dll.size == i + 1
assert isinstance(dll.head, Node)
assert isinstance(dll.head.next, Node)
assert dll.head.prev is None
assert isinstance(dll.tail, Node)
assert isinstance(dll.tail.prev, Node)
assert dll.tail.next is None
assert dll.size == items
assert dll.head.data != dll.tail.data
assert dll.head.data == items - 1
assert dll.tail.data == 0
def test_insert_new_tail_out_of_bounds(self):
dll = LinkedList()
assert dll.is_empty()
assert dll.push(0) is None
assert isinstance(dll.head, Node)
assert isinstance(dll.tail, Node)
assert dll.head is dll.tail
assert dll.size == 1
assert dll.insert(1000, 1) is None
assert isinstance(dll.head, Node)
assert isinstance(dll.tail, Node)
assert dll.head is not dll.tail
assert dll.head.data == 0
assert dll.tail.data == 1
assert dll.head.next is dll.tail
assert dll.head.next.data == 1
assert dll.head.prev is None
assert dll.tail.prev is dll.head
assert dll.tail.prev.data == 0
assert dll.tail.next is None
assert dll.size == 2
def test_insert_end_negative(self):
dll = LinkedList()
assert dll.is_empty()
assert dll.append(0) is None
assert dll.append(1) is None
assert isinstance(dll.head, Node)
assert isinstance(dll.tail, Node)
assert dll.head is not dll.tail
assert dll.size == 2
assert dll.insert(-1, 2) is None
assert isinstance(dll.head, Node)
assert isinstance(dll.tail, Node)
assert dll.head is not dll.tail
assert dll.head.data == 0
assert dll.tail.data == 1
assert dll.head.next is not dll.tail
assert dll.head.next.data == 2
assert dll.head.prev is None
assert dll.tail.prev is not dll.head
assert dll.tail.prev.data == 2
assert dll.tail.next is None
assert dll.size == 3
def test_pop_single_negative(self):
dll = LinkedList()
assert dll.head is None
assert dll.tail is None
assert dll.size == 0
assert dll.push(1) is None
assert isinstance(dll.head, Node)
assert dll.head.next is None
assert dll.head.prev is None
assert isinstance(dll.tail, Node)
assert dll.tail.next is None
assert dll.tail.prev is None
assert dll.head.data == dll.tail.data
assert dll.size == 1
single = dll.pop(-1)
assert isinstance(single, Node)
assert single.data == 1
assert single.next is None
assert single.prev is None
assert dll.head is None
assert dll.tail is None
assert dll.size == 0
def test_remove_single(self):
dll = LinkedList()
assert dll.is_empty()
assert dll.push(1) is None
assert dll.size == 1
assert dll.head is dll.tail
assert dll.remove(1) is None
assert dll.is_empty()
def test_push(self):
dll = LinkedList()
assert dll.head is None
assert dll.tail is None
assert dll.size == 0
assert dll.push(1) is None
assert isinstance(dll.head, Node)
assert isinstance(dll.tail, Node)
assert dll.size == 1
assert dll.head.data == dll.tail.data
assert dll.push(2) is None
assert isinstance(dll.head, Node)
assert isinstance(dll.head.next, Node)
assert dll.head.prev is None
assert isinstance(dll.tail, Node)
assert isinstance(dll.tail.prev, Node)
assert dll.tail.next is None
assert dll.head.next == dll.tail
assert dll.tail.prev == dll.head
assert dll.size == 2
assert dll.head.data != dll.tail.data
assert dll.head.data == 2
assert dll.tail.data == 1
def test_pop_heads(self):
dll = LinkedList()
items = 100
assert dll.head is None
assert dll.tail is None
assert dll.size == 0
for i in range(items):
assert dll.push(i) is None
assert isinstance(dll.head, Node)
assert isinstance(dll.head.next, Node)
assert dll.head.prev is None
assert isinstance(dll.tail, Node)
assert isinstance(dll.tail.prev, Node)
assert dll.tail.next is None
assert dll.size == items
for j in range(items - 1, -1, -1):
assert isinstance(dll.head, Node)
head = dll.pop()
assert isinstance(head, Node)
assert head.data == j
assert dll.size == items - (items - j)
assert dll.head is None
assert dll.tail is None
assert dll.size == 0
def test_sublist_halves(self):
dll = LinkedList()
items = 10
assert dll.head is None
assert dll.size == 0
for i in range(items):
assert dll.push(i) is None
dll.reverse()
def halves(linked_list, begin, end):
mid = linked_list.size // 2
left = sublist(linked_list, begin, mid)
right = sublist(linked_list, mid, end)
return left, right
def print_list(linked_list):
for node in linked_list:
print(node.data, end=',')
print(" ")
def check(linked_list):
if linked_list.size <= 2:
return
left, right = halves(linked_list, 0, linked_list.size)
if linked_list.size % 2: # Odds
assert left.size == (linked_list.size // 2)
assert right.size == (linked_list.size // 2 + 1)
else: # Evens
assert left.size == (linked_list.size // 2)
assert right.size == (linked_list.size // 2)
print_list(left)
print_list(right)
check(left)
check(right)
check(dll)
def test_extend_another_linked_list_from_empty(self):
first = LinkedList()
second = LinkedList()
items = 100
for i in range(items):
assert second.append(i) is None
assert first.is_empty()
assert second.size == items
assert first.extend(second) is None
assert isinstance(first.head, Node)
assert isinstance(first.tail, Node)
assert first.head is not second.head
assert first.tail is not second.tail
assert first.size == second.size
match = 0
for node in first:
assert node.data == match
match += 1
def test_util_sublist_end_out_of_bounds(self):
with pytest.raises(IndexError):
sublist(LinkedList(), 0, 1)
def test_util_sublist_equal_start_and_end(self):
with pytest.raises(IndexError):
sublist(LinkedList(), 0, 0)