def test_delete_node_deletes_a_node_with_no_children_right():
root_node = BinaryTreeNode(5)
child_node = BinaryTreeNode(7)
tree = BinaryTree(root_node)
tree.insert_node(child_node)
tree.delete_node(7)
assert root_node.get_right() == None
def test_delete_node_sets_parent_nodes_right_to_nodes_left_when_only_left():
root_node = BinaryTreeNode(5)
child_node = BinaryTreeNode(7)
test_node = BinaryTreeNode(6)
tree = BinaryTree(root_node)
tree.insert_node(child_node)
tree.insert_node(test_node)
tree.delete_node(7)
assert root_node.get_right() == test_node
assert test_node.get_parent() == root_node
def test_delete_node_sets_node_to_minimum():
root_node = BinaryTreeNode(5)
child_node = BinaryTreeNode(3)
left_node = BinaryTreeNode(2)
right_node = BinaryTreeNode(4)
tree = BinaryTree(root_node)
tree.insert_node(child_node)
tree.insert_node(left_node)
tree.insert_node(right_node)
tree.delete_node(3)
assert root_node.get_left().get_value() == 4
assert root_node.get_left() == child_node
assert child_node.get_value() == 4
assert child_node.get_right() is None
assert child_node.get_left() == left_node
assert left_node.get_parent() == child_node
assert left_node.get_value() == 2
assert left_node.get_parent().get_value() == 4