def create_bst():
btree = BST()
n1 = BSTNode(val=1)
n2 = BSTNode(val=2)
n3 = BSTNode(val=3)
n4 = BSTNode(val=4)
n5 = BSTNode(val=5)
n6 = BSTNode(val=6)
btree.root = n4
btree._size = 6
n4.left_child = n2
n4.right_child = n6
n2.parent = n4
n6.parent = n4
n2.left_child = n1
n2.right_child = n3
n1.parent = n2
n3.parent = n2
n6.left_child = n5
n5.parent = n6
return btree
def create_r_r_tree():
n1 = BSTNode(val=1)
n2 = BSTNode(val=2)
n3 = BSTNode(val=3)
n4 = BSTNode(val=4)
n5 = BSTNode(val=5)
n6 = BSTNode(val=6)
n7 = BSTNode(val=7)
n2.left_child = n1
n2.right_child = n4
n4.left_child = n3
n4.right_child = n6
n6.left_child = n5
n6.right_child = n7
n7.parent = n6
n5.parent = n6
n6.parent = n4
n3.parent = n4
n4.parent = n2
n1.parent = n2
btree = BST()
btree.root = n2
return btree
def test_rotate_left_on_r_r_tree_parentless_and_childless():
pivot = BSTNode(val=2)
newroot = BSTNode(val=3)
n1 = BSTNode(val=1)
pivot.right_child = newroot
pivot.left_child = n1
newroot.parent = pivot
n1.parent = pivot
btree = BST()
btree.root = pivot
btree._rotate_left(pivot=pivot, newroot=newroot)
assert btree.root is newroot
assert newroot.parent is None
assert newroot.right_child is None
assert newroot.left_child is pivot
assert pivot.parent is newroot
assert pivot.left_child is n1
assert n1.parent is pivot
def test_rotate_right_on_l_l_tree_parentless_and_childless():
pivot = BSTNode(val=2)
newroot = BSTNode(val=1)
n3 = BSTNode(val=3)
pivot.right_child = n3
pivot.left_child = newroot
newroot.parent = pivot
n3.parent = pivot
btree = BST()
btree.root = pivot
btree._rotate_right(pivot=pivot, newroot=newroot)
assert btree.root is newroot
assert newroot.parent is None
assert newroot.left_child is None
assert newroot.right_child is pivot
assert pivot.parent is newroot
assert pivot.right_child is n3
assert n3.parent is pivot