Python单元测试断言引发错误

Question

我在 Python 中运行单元测试时遇到了这个奇怪的问题: 我使用了assertRaises，并且运行单元测试引发了正确的异常，但测试仍然失败。好吧，我无法真正解释它，请自行查看回溯:

Error
Traceback (most recent call last):
File "/Users/chianti/PycharmProjects/Programming_Project/Part1and4/Part1and4Test.py", line 32, in test_non_alpha_name
self.assertRaises(RestNameContainNonAlphaError, RestaurantName(self.non_alpha_name))
File "/Users/chianti/PycharmProjects/Programming_Project/Part1and4/InputCheck.py", line 29, in __init__
raise RestNameContainNonAlphaError('There are non alphabetic characters that I can not recognize!')
RestNameContainNonAlphaError: There are non alphabetic characters that I can not recognize!


Error
Traceback (most recent call last):
File "/Users/chianti/PycharmProjects/Programming_Project/Part1and4/Part1and4Test.py", line 24, in test_non_string_name
self.assertRaises(InputNotStringError, RestaurantName, self.non_string_name)
File "/Users/chianti/anaconda/lib/python2.7/unittest/case.py", line 473, in assertRaises
callableObj(*args, **kwargs)
File "/Users/chianti/PycharmProjects/Programming_Project/Part1and4/InputCheck.py", line 33, in __init__
raise InputNotStringError('Not String! The input is supposed to be a string type!')
InputNotStringError: Not String! The input is supposed to be a string type!

为什么？？？？？？？？？？任何想法表示赞赏!谢谢您

<小时/>

这是我的单元测试:

class RestaurantNameTests(unittest.TestCase):

def setUp(self):

    self.non_string_name = 123
    self.valid_name = 'Italian rest '
    self.non_alpha_name = 'valid ** n'

def tearDown(self):

    self.non_string_name = None
    self.valid_name = None
    self.non_alpha_name = None

def test_non_string_name(self):

    with self.assertRaises(InputNotStringError):
        RestaurantName(self.non_string_name)

def test_valid_name(self):

    self.assertEqual(RestaurantName(self.valid_name).__str__(), 'Italian rest')

def test_non_alpha_name(self):

    self.assertRaises(RestNameContainNonAlphaError, RestaurantName(self.non_alpha_name))

如果您需要查看 RestaurantName 的定义，这里是:

class RestaurantName():

def __init__(self, input_contents):

    self.name = input_contents

    if IsValidString(self.name):

        self.no_space_name = self.name.replace(' ', '')

        if str.isalpha(self.no_space_name):
            pass
        else:
            raise RestNameContainNonAlphaError('There are non alphabetic characters that I can not recognize!')

    else:

        raise InputNotStringError('Not String! The input is supposed to be a string type!')

def __repr__(self):

    return 'RestaurantName(%s)' % self.name.strip()  

def __str__(self):

    return self.name.strip() 

再次感谢

Answer 1

回溯与您对问题的描述(也不符合您的代码 FWIW)不匹配。您收到的错误位于 test_non_alpha_name() 中，您没有发布该错误，但从错误消息来看，它看起来像:

self.assertRaises(
    RestNameContainNonAlphaError, 
    RestaurantName(self.non_alpha_name)
    )

这不是使用 assertRaises() 的正确方法。您必须将 ExpectedExceptionClass, callable, *args, **kw 传递给 assertRaises，并且 args 和 kw 将是传递给你的可调用对象。 IOW你想要:

self.assertRaises(
    RestNameContainNonAlphaError, 
    RestaurantName, 
    self.non_alpha_name
    )

原因很简单:按照您当前的调用方式，异常是在调用 assertRaises 之前触发的。

附注:

• 你的tearDown方法没用
• 已经有一个针对错误类型的内置异常，名为 TypeError
• 还有一个针对错误值的内置异常，名为 ValueError