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_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_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_empty(self):
dll = LinkedList()
assert dll.head is None
assert dll.size == 0
with pytest.raises(ValueError):
dll.remove(0)