Python py.test——模拟常量并在测试函数中引发异常

我正在使用py.test和mock。我无法模仿一个常数。我的测试修改分配给常量的dict值。这应该会在我的测试中引发一个异常，但到目前为止还没有。我不确定问题出在哪里，如果能帮我找出问题所在，我将不胜感激。多谢各位

_模块.py

MY_DICT = {'one': 1, 'two': 2, 'three': 3}                                        

class OneMissingException(Exception):                                             
    pass                                                                          

class Test1(object):                                                              
    def __init__(self):                                                           
        self.mydict = MY_DICT                                                     

    @property                                                                     
    def mydict(self):                                                             
        return self._mydict                                                       

    @mydict.setter                                                                
    def mydict(self, mydict):                                                     
        if 'one' not in mydict:                                                   
            raise OneMissingException                                             
        self._mydict = mydict 

import pytest                                                                                                                                                  
from unittest import mock                                                      
from the_module import Test1, OneMissingException                              

@pytest.fixture(scope='function')                                              
def my_dict():                                                                 
    return {'one': 1, 'two': 2, 'three': 3}                                    

def test_verify_test1_exception(my_dict):                                      
    my_dict.pop('one') # comment this out and test still passes                                                       
    with mock.patch("the_module.MY_DICT") as mydict:                           
        mydict.return_value.return_value = my_dict                             
        with pytest.raises(OneMissingException):                               
            Test1()  

测试模块.py

MY_DICT = {'one': 1, 'two': 2, 'three': 3}                                        

class OneMissingException(Exception):                                             
    pass                                                                          

class Test1(object):                                                              
    def __init__(self):                                                           
        self.mydict = MY_DICT                                                     

    @property                                                                     
    def mydict(self):                                                             
        return self._mydict                                                       

    @mydict.setter                                                                
    def mydict(self, mydict):                                                     
        if 'one' not in mydict:                                                   
            raise OneMissingException                                             
        self._mydict = mydict 

import pytest                                                                                                                                                  
from unittest import mock                                                      
from the_module import Test1, OneMissingException                              

@pytest.fixture(scope='function')                                              
def my_dict():                                                                 
    return {'one': 1, 'two': 2, 'three': 3}                                    

def test_verify_test1_exception(my_dict):                                      
    my_dict.pop('one') # comment this out and test still passes                                                       
    with mock.patch("the_module.MY_DICT") as mydict:                           
        mydict.return_value.return_value = my_dict                             
        with pytest.raises(OneMissingException):                               
            Test1()  

---

在您的情况下，您不需要mock（并且您试图以错误的方式使用它，因为没有人调用MY_DICT，您尝试返回_value）

仅使用pytest的monkeypatch夹具：

import pytest                                                                                                                                                  
from unittest import mock                                                      
from the_module import Test1, OneMissingException                              

@pytest.fixture                                              
def patched_my_dict(monkeypatch):                                                                 
    patched = {'one': 1, 'two': 2, 'three': 3}
    monkeypatch.setattr("the_module.MY_DICT", patched)
    return patched                                    

def test_verify_test1_exception(patched_my_dict):                                      
    patched_my_dict.pop('one') # comment this out and test will not pass                                                       
    with pytest.raises(OneMissingException):                               
        Test1()  

---

谢谢你澄清这一点。不过，我不清楚你的解释。您能帮助我理解我是如何错误地修补属性（常量）的吗？