def test_delete_node_without_child(self):
tree = Tree()
tree.add_child(5)
tree.add_child(1)
tree.add_child(4)
tree.add_child(7)
tree.add_child(9)
tree.add_child(6)
tree.add_child(8)
self.assertEqual(tree.display_preorder(), [5, 1, 4, 7, 6, 9, 8])
self.assertEqual(tree.display_inorder(), [1, 4, 5, 6, 7, 8, 9])
tree.delete(4)
self.assertEqual(tree.display_preorder(), [5, 1, 7, 6, 9, 8])
self.assertEqual(tree.display_inorder(), [1, 5, 6, 7, 8, 9])
tree.delete(8)
self.assertEqual(tree.display_preorder(), [5, 1, 7, 6, 9])
self.assertEqual(tree.display_inorder(), [1, 5, 6, 7, 9])
def test_delete_root_node(self):
tree = Tree()
tree.add_child(5)
tree.add_child(4)
tree.add_child(6)
tree.delete(5)
self.assertEqual(tree.display_preorder(), [6, 4])
self.assertEqual(tree.display_inorder(), [4, 6])
def test_display_inorder(self):
tree = Tree()
tree.add_child(5)
tree.add_child(2)
tree.add_child(1)
tree.add_child(4)
tree.add_child(7)
tree.add_child(9)
tree.add_child(6)
tree.add_child(0)
tree.add_child(8)
tree.add_child(3)
self.assertEqual(tree.display_inorder(),
[0, 1, 2, 3, 4, 5, 6, 7, 8, 9])
