text: var { TreeNode, postorderTraversal } = require('./postorderTraversal.js');
  
  var treeNode = new TreeNode(1);
  treeNode.right = new TreeNode(2);
  treeNode.right.left = new TreeNode(3);
  
  describe('145. 二叉树的后序遍历', () => {
    test('示例 1', function() {
      expect(postorderTraversal(treeNode)).toEqual([3, 2, 1]);
    });
  });
  