def test_right_right_case(self):
rbt = RedBlackTree()
rbt.rbt_insert(RedBlackTree.Node(30))
rbt.rbt_insert(RedBlackTree.Node(20))
rbt.rbt_insert(RedBlackTree.Node(40))
rbt.rbt_insert(RedBlackTree.Node(35))
rbt.rbt_insert(RedBlackTree.Node(50))
assert rbt.root.key == 30
assert rbt.root.is_black()
assert rbt.root.left.key == 20
assert rbt.root.left.is_black()
assert rbt.root.right.key == 40
assert rbt.root.right.is_black()
assert rbt.root.right.left.key == 35
assert rbt.root.right.left.is_red()
assert rbt.root.right.right.key == 50
assert rbt.root.right.right.is_red()
rbt.rbt_delete(rbt.root.left)
assert rbt.root.key == 40
assert rbt.root.is_black()
assert rbt.root.left.key == 30
assert rbt.root.left.is_black()
assert rbt.root.left.right.key == 35
assert rbt.root.left.right.is_red()
assert rbt.root.right.key == 50
assert rbt.root.right.is_black()
def test_insert_a_second_node_to_right(self):
rbt = RedBlackTree()
rbt.rbt_insert(RedBlackTree.Node(20))
rbt.rbt_insert(RedBlackTree.Node(30))
assert rbt.root.key == 20
assert rbt.root.is_black()
assert rbt.root.right.key == 30
assert rbt.root.right.is_red()
def test_insert_a_second_node_to_left(self):
rbt = RedBlackTree()
rbt.rbt_insert(RedBlackTree.Node(20))
rbt.rbt_insert(RedBlackTree.Node(10))
assert rbt.root.key == 20
assert rbt.root.is_black()
assert rbt.root.left.key == 10
assert rbt.root.left.is_red()
def test_force_double_rotate_left_then_right(self):
rbt = RedBlackTree()
rbt.rbt_insert(RedBlackTree.Node(20))
rbt.rbt_insert(RedBlackTree.Node(10))
rbt.rbt_insert(RedBlackTree.Node(15))
assert rbt.root.key == 15
assert rbt.root.is_black()
assert rbt.root.left.key == 10
assert rbt.root.left.is_red()
assert rbt.root.right.key == 20
assert rbt.root.right.is_red()
def test_force_left_rotate(self):
rbt = RedBlackTree()
rbt.rbt_insert(RedBlackTree.Node(20))
rbt.rbt_insert(RedBlackTree.Node(30))
rbt.rbt_insert(RedBlackTree.Node(40))
assert rbt.root.key == 30
assert rbt.root.is_black()
assert rbt.root.left.key == 20
assert rbt.root.left.is_red()
assert rbt.root.right.key == 40
assert rbt.root.right.is_red()
def test_force_right_rotate(self):
rbt = RedBlackTree()
rbt.rbt_insert(RedBlackTree.Node(20))
rbt.rbt_insert(RedBlackTree.Node(10))
rbt.rbt_insert(RedBlackTree.Node(5))
assert rbt.root.key == 10
assert rbt.root.is_black()
assert rbt.root.left.key == 5
assert rbt.root.left.is_red()
assert rbt.root.right.key == 20
assert rbt.root.right.is_red()
def test_insert_nodes_to_left_and_right(self):
rbt = RedBlackTree()
rbt.rbt_insert(RedBlackTree.Node(20))
rbt.rbt_insert(RedBlackTree.Node(10))
rbt.rbt_insert(RedBlackTree.Node(30))
assert rbt.root.key == 20
assert rbt.root.is_black()
assert rbt.root.left.key == 10
assert rbt.root.left.is_red()
assert rbt.root.right.key == 30
assert rbt.root.right.is_red()
def four_node_factory(self):
rbt = RedBlackTree()
rbt.rbt_insert(RedBlackTree.Node(30))
rbt.rbt_insert(RedBlackTree.Node(40))
rbt.rbt_insert(RedBlackTree.Node(20))
rbt.rbt_insert(RedBlackTree.Node(10))
assert rbt.root.key == 30
assert rbt.root.is_black()
assert rbt.root.left.key == 20
assert rbt.root.left.is_black()
assert rbt.root.right.key == 40
assert rbt.root.right.is_black()
assert rbt.root.left.left.key == 10
assert rbt.root.left.left.is_red()
return rbt
def test_can_change_from_red_to_black_and_back(self):
node = RedBlackTree.Node(20)
assert node.is_red()
node.color = BLACK
assert node.is_black()
node.color = RED
assert node.is_red()
def test_initialization(self):
node = RedBlackTree.Node(20)
assert isinstance(node, RedBlackTree.Node)
assert node.is_red()
def test_insert_root_into_red_black_tree(self):
rbt = RedBlackTree()
rbt.rbt_insert(RedBlackTree.Node(20))
assert rbt.root.key == 20
assert rbt.root.is_black()