Python 单元测试用例错误：正好需要 2 个参数给出 3 个

如何解决Python 单元测试用例错误：正好需要 2 个参数给出 3 个

在运行 Python Binary Search Tree Traversal 测试用例时遇到问题。它给出了一个错误：

======================================================================
ERROR: test_case_1 (__main__.TestProgram)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "BST_traversal.py",line 31,in test_case_1
    self.assertEqual(root.inorderTraversal(root,[]),inorder)
TypeError: inorderTraversal() takes exactly 2 arguments (3 given)

----------------------------------------------------------------------
Ran 1 test in 0.000s

Failed (errors=1)

BST 的代码是：

import unittest

class BST:
    def __init__(self,value):
        self.value = value
        self.left = None
        self.right = None

    def inorderTraversal(self,array):
        if self is not None:
            inorderTraversal(self.left,array)
            array.append(self.value)
            inorderTraversal(self.right,array)
        return array

class TestProgram(unittest.TestCase):
    def test_case_1(self):
        root = BST(10)
        
        root.left = BST(5)
        root.left.left = BST(2)
        root.left.left.left = BST(1)
        root.left.right = BST(5)
        root.right = BST(15)
        root.right.right = BST(22)

        inorder = [1,2,5,10,15,22]
        preOrder = [10,1,22]
        postorder = [1,22,10]

        self.assertEqual(root.inorderTraversal(root,inorder)

if __name__ == '__main__':
    unittest.main()

即使在为 BST 开设了一个单独的课程后，也对我没有太大帮助。

解决方法

self 是一个隐藏参数，你不需要给出

import unittest


class BST:
    def __init__(self,value):
        self.value = value
        self.left = None
        self.right = None

    def inOrderTraversal(self,data,array):
        if data is not None:
            data.inOrderTraversal(data.left,array)
            array.append(data.value)
            data.inOrderTraversal(data.right,array)
        return array


class TestProgram(unittest.TestCase):
    def test_case_1(self):
        root = BST(10)

        root.left = BST(5)
        root.left.left = BST(2)
        root.left.left.left = BST(1)
        root.left.right = BST(5)
        root.right = BST(15)
        root.right.right = BST(22)

        inOrder = [1,2,5,10,15,22]
        preOrder = [10,1,22]
        postOrder = [1,22,10]
        arr = root.inOrderTraversal(root,[])
        print(arr)
        self.assertEqual(arr,inOrder)


if __name__ == '__main__':
    unittest.main()

.
[1,22]

,

import unittest

class BST:
    def __init__(self,array):
        if self and self.left:
            self.left.inOrderTraversal(array)
        if self:
            array.append(self.value)
        if self and self.right:
            self.right.inOrderTraversal(array)
        return array

class TestProgram(unittest.TestCase):
    def test_case_1(self):
        root = BST(10)

        root.left = BST(5)
        root.left.left = BST(2)
        root.left.left.left = BST(1)
        root.left.right = BST(5)
        root.right = BST(15)
        root.right.right = BST(22)

        inOrder = [1,10]

        self.assertEqual(root.inOrderTraversal([]),inOrder)

if __name__ == '__main__':
    unittest.main()

那应该可以运行。您已经非常接近了，只需要了解 self 参数的工作原理。另外 is not None 是多余的，仅供参考。