class BinarySearchTreeDeleteTestCase(unittest.TestCase):
def setUp(self):
self.tree = BinarySearchTree()
self.seven = self.tree.insert(7, 'seven')
self.fifteen = self.tree.insert(15, 'fifteen')
self.eight = self.tree.insert(8, 'eight')
self.fourteen = self.tree.insert(14, 'fourteen')
self.nine = self.tree.insert(9, 'nine')
def test_return_deleted_node(self):
delete_node = self.tree.delete(8)
self.assertEqual(delete_node, self.eight)
def test_set_deleted_node_properties_to_none(self):
delete_node = self.tree.delete(8)
self.assertEqual(delete_node.parent, None)
self.assertEqual(delete_node.left, None)
self.assertEqual(delete_node.right, None)
def test_replace_deleted_node_with_smaller_child(self):
self.tree.delete(8)
# in this tree, node "14" should replace the deleted node "8"
self.assertEqual(self.fifteen.left, self.fourteen)
self.assertEqual(self.fourteen.parent, self.fifteen)
self.assertEqual(self.fourteen.left, self.nine)
class BinarySearchTreeTraversalsTestCase(unittest.TestCase):
def setUp(self):
self.tree = BinarySearchTree()
self.tree.insert(7, '7')
self.tree.insert(4, '4')
self.tree.insert(9, '9')
self.tree.insert(2, '2')
self.tree.insert(5, '5')
self.tree.insert(8, '8')
self.tree.insert(12, '12')
def test_preorder_should_return_array_of_preordered_values(self):
values = self.tree.traverse_preorder()
expected = ['7', '4', '2', '5', '9', '8', '12']
self.assertSequenceEqual(values, expected)
def test_inorder_should_return_array_of_inordered_values(self):
values = self.tree.traverse_inorder()
expected = ['2', '4', '5', '7', '8', '9', '12']
self.assertSequenceEqual(values, expected)
def test_postorder_should_return_array_of_postordered_values(self):
values = self.tree.traverse_postorder()
expected = ['2', '5', '4', '8', '12', '9', '7']
self.assertSequenceEqual(values, expected)
class BinarySearchTreeGetTestCase(unittest.TestCase):
def setUp(self):
self.tree = BinarySearchTree()
self.tree.insert(2, 'two')
self.tree.insert(1, 'one')
self.tree.insert(3, 'three')
def test_return_value_of_the_given_key(self):
value = self.tree.get(2)
self.assertEqual(value, 'two')
value = self.tree.get(1)
self.assertEqual(value, 'one')
value = self.tree.get(3)
self.assertEqual(value, 'three')
class BinarySearchTreeInsertTestCase(unittest.TestCase):
def setUp(self):
self.tree = BinarySearchTree()
def test_first_inserted_value_should_be_root(self):
# insert a node
inserted_node = self.tree.insert(1, 'one')
# inserted node should be root
self.assertEqual(self.tree.root, inserted_node)
# insert another node
new_node = self.tree.insert(2, '2')
# root should be inserted_root pa rin
self.assertEqual(self.tree.root, inserted_node)
def test_should_set_node_properties_properly(self):
root_two = self.tree.insert(2, 'two')
self.assertEqual(root_two.parent, None)
self.assertEqual(root_two.left, None)
self.assertEqual(root_two.right, None)
# insert another node
one = self.tree.insert(1, 'one')
self.assertEqual(one.parent, root_two)
self.assertEqual(one.left, None)
self.assertEqual(one.right, None)
# root_two left child should be one
self.assertEqual(root_two.left, one)
# insert new node
four = self.tree.insert(4, 'four')
self.assertEqual(four.parent, root_two)
self.assertEqual(four.left, None)
self.assertEqual(four.right, None)
# root_two right child should be four
self.assertEqual(root_two.right, four)
class BinarySearchTreeMinimumMaximumTestCase(unittest.TestCase):
def setUp(self):
self.tree = BinarySearchTree()
self.tree.insert(7, 'seven')
self.tree.insert(15, 'fifteen')
self.tree.insert(8, 'eight')
self.tree.insert(14, 'fourteen')
def test_minimum_should_return_the_value_of_the_minimum_key_in_the_tree(
self):
minimum = self.tree.minimum()
self.assertEqual(minimum, 'seven')
def test_maximum_should_return_the_value_of_the_maximum_key_in_the_tree(
self):
maximum = self.tree.maximum()
self.assertEqual(maximum, 'fifteen')