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_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_another_linked_list(self):
first = LinkedList()
second = LinkedList()
items = 100
for i in range(items):
assert first.append(i) is None
for j in range(items, items * 2):
assert second.append(j) is None
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 == items * 2
match = 0
for node in first:
assert node.data == match
match += 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_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_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_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_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_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