def test_pred(self):
import random
random.seed(7477)
entries = get_random_entries()
tree = AVLTree(entries)
with self.subTest(f"test pred found"):
pred, prev = None, None
for entry in tree.traverse():
try:
pred = tree.pred(entry)
except KeyError:
self.assertIsNone(prev)
self.assertEqual(prev, pred)
prev = entry
with self.assertRaises(KeyError) as context:
tree.pred(1000000)
self.assertIn("Predecessor of 1000000 not found.",
str(context.exception))
