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_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_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_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_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_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_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_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_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_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_is_empty(self):
dll = LinkedList()
assert dll.head is None
assert dll.tail is None
assert dll.size == 0
assert dll.is_empty() is True
def test_clear_empty(self):
dll = LinkedList()
assert dll.is_empty()
assert dll.clear() is None
assert dll.is_empty()