def test_is_valid_binary_search_tree_three_levels_false(self):
"""
In a valid sort tree, depth first in order traversal produces a sorted list.
This tree is not a valid binary search tree.
https://en.wikipedia.org/wiki/Binary_search_tree
20
/ \
/ \
/ \
10 30
/ \
5 40
"""
node0 = binary_node.BinaryNode(20)
node1 = binary_node.BinaryNode(10)
node2 = binary_node.BinaryNode(30)
node3 = binary_node.BinaryNode(5)
node4 = binary_node.BinaryNode(40)
node0.left = node1
node0.right = node2
node2.left = node3
node2.right = node4
self.assertFalse(binary_tree.is_valid_binary_search_tree(node0))
def test_init(self):
node0_value = 3
node0 = binary_node.BinaryNode(node0_value)
self.assertIsNotNone(node0)
self.assertEqual(node0.value, node0_value)
self.assertIsNone(node0.left)
self.assertIsNone(node0.right)
node1_value = 8
node1 = binary_node.BinaryNode(node1_value)
node0.left = node1
self.assertEqual(node0.left, node1)
def test_is_valid_binary_search_tree_two_levels_false(self):
"""
3
/ \
/ \
/ \
2 1
"""
node0 = binary_node.BinaryNode(3)
node0.left = binary_node.BinaryNode(2)
node0.right = binary_node.BinaryNode(1)
self.assertFalse(binary_tree.is_valid_binary_search_tree(node0))
def test_is_leaf_node(self):
node0_value = 3
node0 = binary_node.BinaryNode(node0_value)
self.assertIsNotNone(node0)
self.assertEqual(node0.value, node0_value)
self.assertIsNone(node0.left)
self.assertIsNone(node0.right)
self.assertTrue(node0.is_leaf_node())
node1_value = 8
node1 = binary_node.BinaryNode(node1_value)
node0.left = node1
self.assertEqual(node0.left, node1)
self.assertFalse(node0.is_leaf_node())
def test_is_valid_binary_search_tree_repeated(self):
"""
3
/ \
/ \
/ \
2 7
/
2
"""
node0 = binary_node.BinaryNode(3)
node0.left = binary_node.BinaryNode(2)
node0.right = binary_node.BinaryNode(7)
# no repeated values
self.assertTrue(binary_tree.is_valid_binary_search_tree(node0))
# add repeated value to make tree invalid
node0.right.left = binary_node.BinaryNode(2)
self.assertFalse(binary_tree.is_valid_binary_search_tree(node0))
def test_is_valid_binary_search_tree_one_level_true(self):
"""
-5
"""
node0 = binary_node.BinaryNode(-5)
# explicitly set left, don't explicitly set right
node0.left = None
self.assertIsNone(node0.left)
self.assertIsNone(node0.right)
self.assertTrue(binary_tree.is_valid_binary_search_tree(node0))
def test_is_valid_binary_search_tree_three_levels_child_none(self):
"""
5
/ \
/ \
/ \
3 7
/ \ /
2 4 6
"""
node0 = binary_node.BinaryNode(5)
node1 = binary_node.BinaryNode(3)
node2 = binary_node.BinaryNode(7)
node3 = binary_node.BinaryNode(2)
node4 = binary_node.BinaryNode(4)
node5 = binary_node.BinaryNode(6)
node0.left = node1
node0.right = node2
node1.left = node3
node1.right = node4
node2.left = node5
self.assertTrue(binary_tree.is_valid_binary_search_tree(node0))
def test_is_valid_binary_search_tree_four_levels(self):
"""
5
/ \
/ \
/ \
4 7
/ \ /
2 9 6
/ \
8 11
"""
node0 = binary_node.BinaryNode(5)
node1 = binary_node.BinaryNode(4)
node2 = binary_node.BinaryNode(7)
node3 = binary_node.BinaryNode(2)
node4 = binary_node.BinaryNode(9)
node5 = binary_node.BinaryNode(6)
node6 = binary_node.BinaryNode(8)
node7 = binary_node.BinaryNode(11)
node0.left = node1
node0.right = node2
node1.left = node3
node1.right = node4
node2.left = node5
node4.left = node6
node4.right = node7
self.assertFalse(binary_tree.is_valid_binary_search_tree(node0))
# manually check subtrees
self.assertTrue(binary_tree.is_valid_binary_search_tree(node1))
self.assertTrue(binary_tree.is_valid_binary_search_tree(node2))
self.assertTrue(binary_tree.is_valid_binary_search_tree(node3))
self.assertTrue(binary_tree.is_valid_binary_search_tree(node4))