def test_rotate_right_should_make_previous_root_a_right_child_to_new_root():
new_root = Node(value=2, right=Node(value=99))
previous_root = Node(value=1, left=new_root)
rotate_right(subtree_root=previous_root)
assert new_root.right is previous_root
def test_rotate_right_should_raise_an_error_when_new_root_has_no_right_child():
new_root_value = 22
new_root = Node(value=new_root_value)
with pytest.raises(MissingRightChildOfNodeError) as err:
rotate_right(subtree_root=Node(value=33, left=new_root))
assert f"{new_root_value}" in str(err)
def test_rotate_right_should_raise_an_error_when_subtree_root_has_no_left_child(
):
root_value = 33
with pytest.raises(MissingLeftChildOfNodeError) as err:
rotate_right(subtree_root=Node(value=root_value))
assert f"{root_value}" in str(err)
def test_rotate_right_should_not_change_left_child_of_new_root():
left_child_of_new_root = Node(value=3)
new_root = Node(value=2, left=left_child_of_new_root, right=Node(value=88))
previous_root = Node(value=1, left=new_root)
rotate_right(subtree_root=previous_root)
assert new_root.left is left_child_of_new_root
def test_rotate_right_should_make_new_root_right_child_a_left_child_to_previous_root(
):
right_child_of_new_root = Node(value=2)
new_root = Node(value=3, right=right_child_of_new_root)
previous_root = Node(value=2, left=new_root)
rotate_right(subtree_root=previous_root)
assert previous_root.left is right_child_of_new_root
def test_rotate_right_should_not_change_right_child_of_previous_root():
right_child_of_previous_root = Node(value=0)
new_root = Node(value=3, right=Node(value=77))
previous_root = Node(value=1,
left=new_root,
right=right_child_of_previous_root)
rotate_right(subtree_root=previous_root)
assert previous_root.right is right_child_of_previous_root
def insert(self, value: int) -> None:
if self.is_empty():
# Case_I3: N is the root and red
self.__root = ColorNode(value=value, is_red=False)
return
current: Optional[ColorNode] = self.__root
while current is not None:
if value == current.value:
raise DuplicatedValueInTreeError(
f"Value {value} is already present")
previous = current
current = current.left if value < current.value else current.right
current = ColorNode(value=value, is_red=True, parent=previous)
if current.value > previous.value:
previous.right = current
else:
previous.left = current
if not current.parent.is_red:
# Case_I1 (P is black)
return
if current.parent.parent is None:
# Case_I4
current.parent.is_red = False
return
if current.is_uncle_black():
# Case_I6
if current is current.parent.right:
new_subtree_root = rotate_left(
subtree_root=current.parent.parent)
new_subtree_root.is_red = False
new_subtree_root.left.is_red = True
else:
new_subtree_root = rotate_right(
subtree_root=current.parent.parent)
new_subtree_root.is_red = False
new_subtree_root.right.is_red = True
if new_subtree_root.parent is None:
self.__root = new_subtree_root