def test_preorder_traversal(self):
"""Test that a preorder traversal returns the nodes
in the BST in the correct order.
"""
#Tree should look like this
# 23
# 12 34
# 9 15 45
# 56
bst = BinarySearchTree()
self.assertEqual(bst.size, 0)
self.assertEqual(bst.get_height(), -1)
nodes = bst.traverse(TreeTraversalOrder.PRE_ORDER)
for node in nodes:
self.assertIsNone(node)
nodes = [23, 12, 34, 9, 15, 45, 56]
#add nodes
for node in nodes:
bst.insert(node)
self.assertEqual(bst.get_height(), 3)
self.assertEqual(bst.size, 7)
#order should be 23, 12 9, 15, 34, 45, 56
i = 0
preorder = [23, 12, 9, 15, 34, 45, 56]
for node in bst.traverse(TreeTraversalOrder.PRE_ORDER):
self.assertEqual(preorder[i], node.data)
i += 1
def test_level_order_traversal(self):
"""Test that a levelorder traversal returns the nodes
in the BST in the correct order.
"""
#Tree should look like this
# 23
# 12 34
# 9 15 45
# 56
bst = BinarySearchTree()
self.assertEqual(bst.size, 0)
self.assertEqual(bst.get_height(), -1)
nodes = bst.traverse(TreeTraversalOrder.IN_ORDER)
for node in nodes:
self.assertIsNone(node)
nodes = [23, 12, 34, 9, 15, 45, 56]
#add nodes
for node in nodes:
bst.insert(node)
self.assertEqual(bst.get_height(), 3)
self.assertEqual(bst.size, 7)
#this is the expected order
i = 0
level_order = [23, 12, 34, 9, 15, 45, 56]
for node in bst.traverse(TreeTraversalOrder.LEVEL_ORDER):
self.assertEqual(level_order[i], node.data)
i += 1
def test_invalid_traversal(self):
"""Test to ensure that the traverse method
returns an empty generator.
"""
#Tree should look like this
# 23
# 12 34
# 9 15 45
# 56
bst = BinarySearchTree()
self.assertEqual(bst.size, 0)
#add level 1
bst.insert(23)
#add level 2
bst.insert(12)
bst.insert(34)
#add level 3
bst.insert(9)
bst.insert(15)
bst.insert(45)
#add level 4
bst.insert(56)
self.assertEqual(bst.size, 7)
nodes = bst.traverse(5)
for node in nodes:
self.assertIsNone(node)