def test_right_left_conversion_six_nodes():
"""
Test that given six nodes in a left-right state converts to left-left.
"""
from bst import Bst, Node
new_bst = Bst()
node1 = Node(10)
node2 = Node(5)
node3 = Node(15)
node4 = Node(20)
node5 = Node(14)
node6 = Node(13)
new_bst.head = node1
node1.left = node2
node2.parent = node1
node1.right = node3
node3.parent = node1
node3.right = node4
node4.parent = node3
node3.left = node5
node5.parent = node3
node5.left = node6
node6.parent = node5
new_bst.head.right_left_conversion()
assert new_bst.head.right == node5
assert new_bst.head.right.right == node3
assert new_bst.head.right.right.right == node4
def test_bst_parent_setter_parent_child_left():
"""test that parent setter sets child left properly"""
from bst import Node
node1 = Node(2)
node2 = Node(1)
node2.parent = node1
assert node1.left.val == node2.val
def test_bst_parent_setter_child_parent():
"""test parent setter works properly"""
from bst import Node
node1 = Node(1)
node2 = Node(2)
node2.parent = node1
assert node1.val == node2.parent.val
def test_left_rotation_three_nodes():
"""Test that a right-right becomes balanced."""
from bst import Bst, Node
new_bst = Bst()
node1 = Node(10)
node2 = Node(15)
node3 = Node(20)
new_bst.head = node1
node1.right = node2
node2.parent = node1
node2.right = node3
node3.parent = node2
new_bst.head.left_rotation()
assert node2.parent is None
assert node2.left == node1
assert node2.right == node3
assert node2.left.parent == node2
def test_right_left_conversion_three_nodes():
"""
Test that given three nodes in a right-left state converts to right-right.
"""
from bst import Bst, Node
new_bst = Bst()
node1 = Node(10)
node2 = Node(15)
node3 = Node(12)
new_bst.head = node1
node1.right = node2
node2.parent = node1
node2.left = node3
node3.parent = node2
new_bst.head.right_left_conversion()
assert new_bst.head.right == node3
assert new_bst.head.right.right == node2
assert new_bst.head.right.right.parent == node3
assert new_bst.head.right.parent == node1
