def test_insert_many_times_balance():
"""Test self balancing tree still balanced after 50 random insertions."""
from bst import AVLBST
avl = AVLBST()
for _ in range(50):
random_int = random.randint(1, 1000)
avl.insert(random_int)
assert avl.balance() == 1 or avl.balance() == 0 or avl.balance() == -1
def test_avlbst_delete_method_balances():
"""Test tree is balanced after delete method."""
from bst import AVLBST
avl = AVLBST()
avl.insert(5)
avl.insert(3)
avl.insert(2)
avl.insert(7)
avl.delete(7)
assert avl.root.val == 3
assert avl.root.right.val == 5
assert avl.root.left.val == 2
def test_avlbst_balances_on_insert_right_right():
"""Test tree self balances with a left rotation."""
from bst import AVLBST
avl = AVLBST()
avl.insert(5)
avl.insert(6)
avl.insert(7)
assert avl.root.val == 6
assert avl.root.right.val == 7
assert avl.root.left.val == 5
def test_avlbst_balances_on_insert_left_right():
"""Test tree self balances with left right rotation."""
from bst import AVLBST
avl = AVLBST()
avl.insert(5)
avl.insert(3)
avl.insert(4)
assert avl.root.val == 4
assert avl.root.right.val == 5
assert avl.root.left.val == 3
def test_avlbst_balances_on_insert_left_left():
"""Test AVLBST balances itself on insert two left."""
from bst import AVLBST
avl = AVLBST()
avl.insert(5)
avl.insert(4)
avl.insert(3)
assert avl.root.val == 4
assert avl.root.right.val == 5
assert avl.root.left.val == 3
def test_self_balancing_after_many_rotations():
"""Test all balance methods work in tandom."""
from bst import AVLBST
bst = AVLBST([50, 25, 15, 60, 70, 10, 12, 80, 75])
assert bst.root.val == 60
assert bst.root.left.val == 25
assert bst.root.left.left.val == 12
assert bst.root.left.left.left.val == 10
assert bst.root.left.left.right.val == 15
assert not bst.root.left.left.left.right
assert not bst.root.left.left.left.left
assert bst.root.left.right.val == 50
assert not bst.root.left.right.right
assert not bst.root.left.right.left
assert bst.root.right.val == 75
assert bst.root.right.right.val == 80
assert not bst.root.right.right.right
assert not bst.root.right.right.left
assert bst.root.right.left.val == 70
assert not bst.root.right.left.left
assert not bst.root.right.left.right
def test_insert_items_rebal_right_left_rotation():
"""Test that the tree rebalances on a left right rotation."""
from bst import AVLBST
avl = AVLBST()
avl.insert(85)
avl.insert(2)
avl.insert(88)
avl.insert(79)
avl.insert(55)
assert avl.root.val == 85
assert avl.root.right.val == 88
assert avl.root.left.val == 55
assert avl.root.left.left.val == 2
assert avl.root.left.right.val == 79
avl.insert(50)
assert avl.balance() == 1 or avl.balance() == 0 or avl.balance() == -1
assert avl.root.val == 55
def test_avlbst_class_inherits_bst():
"""Test the AVLBST class inherits bst methods."""
from bst import AVLBST
avlbst = AVLBST()
avlbst.insert(5)
assert avlbst.root.val == 5