def test_delete_lone_leftmost_rightsubtree_child_with_right_child():
binary_search_tree = BinarySearchTree()
binary_search_tree.insert(1)
binary_search_tree.insert(0)
binary_search_tree.insert(3)
binary_search_tree.insert(2)
binary_search_tree.insert(6)
binary_search_tree.insert(4)
binary_search_tree.insert(5)
binary_search_tree.insert(7)
node = binary_search_tree.search(3)
binary_search_tree.delete(node)
traversed_list = []
action = lambda node: traversed_list.append(node.value)
binary_search_tree.traverse(action)
new_node = binary_search_tree.search(4)
new_left_child_node = binary_search_tree.search(2)
new_right_child_node = binary_search_tree.search(6)
new_left_of_right_child_node = binary_search_tree.search(5)
assert traversed_list == [0, 1, 2, 4, 5, 6, 7]
assert new_node.parent is binary_search_tree.root
assert binary_search_tree.root.right is new_node
assert new_node.left is new_left_child_node
assert new_left_child_node.parent is new_node
assert new_node.right is new_right_child_node
assert new_right_child_node.parent is new_node
assert new_right_child_node.left is new_left_of_right_child_node
assert new_left_of_right_child_node.parent is new_right_child_node
def test_delete_lone_root_node():
binary_search_tree = BinarySearchTree()
binary_search_tree.insert(0)
node = binary_search_tree.search(0)
binary_search_tree.delete(node)
traversed_list = []
action = lambda node: traversed_list.append(node.value)
binary_search_tree.traverse(action)
assert traversed_list == []
def test_traverse():
binary_search_tree = BinarySearchTree()
traversed_list = []
action = lambda node: traversed_list.append(node.value)
N = 10
seq = list(range(N))
random.shuffle(seq)
for i in seq:
binary_search_tree.insert(i)
binary_search_tree.traverse(action)
assert traversed_list == list(range(N))
def test_delete_lone_node_left_from_parent_root():
binary_search_tree = BinarySearchTree()
binary_search_tree.insert(1)
binary_search_tree.insert(0)
binary_search_tree.insert(2)
node = binary_search_tree.search(0)
binary_search_tree.delete(node)
traversed_list = []
action = lambda node: traversed_list.append(node.value)
binary_search_tree.traverse(action)
parent_node = binary_search_tree.search(1)
assert traversed_list == [1, 2]
assert parent_node.left is None
def test_delete_root_node_only_right_child():
binary_search_tree = BinarySearchTree()
binary_search_tree.insert(0)
binary_search_tree.insert(2)
binary_search_tree.insert(1)
binary_search_tree.insert(3)
node = binary_search_tree.search(0)
binary_search_tree.delete(node)
traversed_list = []
action = lambda node: traversed_list.append(node.value)
binary_search_tree.traverse(action)
new_node = binary_search_tree.search(2)
assert traversed_list == [1, 2, 3]
assert new_node is binary_search_tree.root
assert new_node.parent is None
def test_delete_only_right_child_right_from_parent():
binary_search_tree = BinarySearchTree()
binary_search_tree.insert(0)
binary_search_tree.insert(1)
binary_search_tree.insert(3)
binary_search_tree.insert(2)
binary_search_tree.insert(4)
node = binary_search_tree.search(1)
binary_search_tree.delete(node)
traversed_list = []
action = lambda node: traversed_list.append(node.value)
binary_search_tree.traverse(action)
new_node = binary_search_tree.search(3)
new_node_parent = binary_search_tree.search(0)
assert traversed_list == [0, 2, 3, 4]
assert new_node.parent is new_node_parent
assert new_node_parent.right is new_node
def test_delete_root_node_lone_leftmost_rightsubtree_child():
binary_search_tree = BinarySearchTree()
binary_search_tree.insert(1)
binary_search_tree.insert(0)
binary_search_tree.insert(3)
binary_search_tree.insert(2)
binary_search_tree.insert(4)
node = binary_search_tree.search(1)
binary_search_tree.delete(node)
traversed_list = []
action = lambda node: traversed_list.append(node.value)
binary_search_tree.traverse(action)
new_node = binary_search_tree.search(2)
new_child_node = binary_search_tree.search(0)
assert traversed_list == [0, 2, 3, 4]
assert new_node is binary_search_tree.root
assert new_node.parent is None
assert new_node.left is new_child_node
assert new_child_node.parent is new_node