pytest在辅助函数中断言内省

Question

pytest确实很棒,assert introspection因此很容易找到字符串的差异,特别是如果差异在白色空间中.现在我使用了一个稍微复杂的测试助手,我在许多测试用例中重用了它.帮助器也有自己的模块,对于那个模块,我想添加断言内省.

helpers.py:

...
def my_helper():
    assert 'abcy' == 'abcx'

test_mycase.py:

from .helpers import my_helper


def test_assert_in_tc():
    assert 'abcy' == 'abcx'


def test_assert_in_helper():
    my_helper()

测试报告显示测试中断言的有用信息,但是not for asserts within the helper:

=============================================================== FAILURES ================================================================
___________________________________________________________ test_assert_in_tc ___________________________________________________________

    def test_assert_in_tc():
>       assert 'abcy' == 'abcx'
E       assert 'abcy' == 'abcx'
E         - abcy
E         ?    ^
E         + abcx
E         ?    ^

tests/test_pytest_assert.py:9: AssertionError
_________________________________________________________ test_assert_in_helper _________________________________________________________

    def test_assert_in_helper():
>       my_helper()

tests/test_pytest_assert.py:13: 
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

    def my_helper():
>       assert 'abcy' == 'abcx'
E       AssertionError

tests/helpers.py:258: AssertionError
======================================================= 2 failed in 0.24 seconds ========================================================

作为一种解决方法,我使用断言输出附加信息,但输出看起来仍然很奇怪并使代码爆炸.任何想法如何激活pytest断言辅助文件中的内省？

我发现了一个不同但相关的问题,遗憾的是我到目前为止无法解决这个问题:

import pytest
from .helpers import my_helper
pytest.register_assert_rewrite('helpers.my_helper')

Answer 1

我不得不将register_assert_rewrite放入tests/__ init__.py中,如下所示:

import pytest

# we want to have pytest assert introspection in the helpers
pytest.register_assert_rewrite('tests.helpers')