def test_empty_tree(self, node=None):
self.assertTrue(self.a.is_AVLTree(node)) # empty tree is AVL tree
self.assertEqual(height(node), 0) # height of empty tree equals 0
node = self.a.delete(node, 5) # removing not existing node should work
self.assertEqual(height(node), 0)
def test_for_single_node(self, node=None):
key = 2
node = self.a.insert(node, key)
self.assertEqual(height(node), 1) # height of single node equals 0
node = self.a.delete(node, 5)
self.assertEqual(node.key, key) # removing not existing node
self.assertTrue(self.a.is_AVLTree(node)) # must be AVL tree
node = self.a.delete(node, key)
self.assertEqual(height(node), 0) # removing existing node
self.assertEqual(node, None) # node was deleted
def test_insert_right_left(self, node=None):
# right rotation 10, then left rotation 20
node = self.a.insert(node, 20)
node = self.a.insert(node, 1)
node = self.a.insert(node, 10)
node = self.a.insert(node, 5)
node = self.a.insert(node, 21)
node = self.a.insert(node, 7)
node = self.a.insert(node, 19)
self.assertTrue(self.a.is_AVLTree(node))
self.assertEqual(height(node), 3)
self.assertEqual(self.a.get_balance(node), 0)