在测试用例中的 setUp 或 setUpClass 中修补装饰器不起作用 [英] Patching decorator in setUp or setUpClass in TestCases does not work

问题描述

我试图在 unittest.TestCase 子类的 setUp 或 setUpClass 方法中修补一些函数.

I am trying to patch some functions during either the setUp or setUpClass methods of a unittest.TestCase subclass.

给定一个模块 patch_me_not.py

# patch_me_not.py
def patch_me(at):
    print('I am not patched at {}.'.format(at))

def patch_me_not(at):
    patch_me(at)

以下脚本产生的输出超出了我的预期.

The following script produces more output that I would expect.

# main.py
import unittest
from unittest.mock import patch
from patch_me_not import patch_me_not


@patch('patch_me_not.patch_me', lambda x: None)
class PatchMeNotTests(unittest.TestCase):

    @classmethod
    def setUpClass(cls):
        print('I am the setUpClass.')
        patch_me_not('setUpClass')

    def setUp(self):
        print('I am the setUp.')
        patch_me_not('setUp')

    def test_print(self):
        print('I am the test')
        patch_me_not('test_print')


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

测试脚本输出为

I am the setUpClass.
I am not patched at setUpClass.
I am the setUp.
I am not patched at setUp.
I am the test
.
----------------------------------------------------------------------
Ran 1 test in 0.000s

OK

如果补丁在 setUp 和 setUpClass 中工作，我不希望输出中出现两行I am not patched at...".

Where I would not expect the two "I am not patched at..." lines in the output if the patch worked in setUp and setUpClass.

如何才能在这些方法中应用模拟补丁?

How can I get the mock patch to be applied in these methods?

推荐答案

我认为你需要这样做:

class PatchMeNotTests(unittest.TestCase):

    @classmethod
    @patch('patch_me_not.patch_me', lambda x: None)
    def setUpClass(cls):
        print('I am the setUpClass.')
        patch_me_not('setUpClass')

    @patch('patch_me_not.patch_me', lambda x: None)
    def setUp(self):
        print('I am the setUp.')
        patch_me_not('setUp')

    def test_print(self):
        print('I am the test')
        patch_me_not('test_print')

修补您的测试用例不起作用，因为当将 patch 应用于 TestCase 时，它仅 修补测试方法或更具体地说:方法以可配置的前缀 patch.TEST_PREFIX 开头，默认值为 "test".这就是您的解决方案不起作用的原因.

Patching your test case did not work because when patch is applied to TestCase it patches only test methods or to be more specific: methods that start with a configurable prefix patch.TEST_PREFIX which default value is "test". That's why your solution did not work.

这是来自 unittest 文档的相关引用

Here is relevant quote from unittest docs

Patch 可以用作 TestCase 类装饰器.它的工作原理装饰类中的每个测试方法.这减少了样板当您的测试方法共享一个通用补丁集时，补丁()通过查找以开头的方法名称来查找测试patch.TEST_PREFIX.默认情况下，这是'test'，匹配方式unittest 查找测试.您可以通过设置指定替代前缀patch.TEST_PREFIX.

Patch can be used as a TestCase class decorator. It works by decorating each test method in the class. This reduces the boilerplate code when your test methods share a common patchings set. patch() finds tests by looking for method names that start with patch.TEST_PREFIX. By default, this is 'test', which matches the way unittest finds tests. You can specify an alternative prefix by setting patch.TEST_PREFIX.

这篇关于在测试用例中的 setUp 或 setUpClass 中修补装饰器不起作用的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！