python - 混合参数化测试和标记

Question

好吧，我正在为一件让我大吃一惊的事情而苦苦挣扎。

虽然我的实际代码不同，但这基本上确定了问题。假设此示例代码:

import pytest

@pytest.mark.parametrize('type',(
    pytest.param('stability', marks=pytest.mark.stability),
    pytest.param('integration', marks=pytest.mark.integration),
))
@pytest.mark.integration
@pytest.mark.stability
def test_meh(type):
    assert type == 'integration'

下面是运行该测试的输出。

$pytest -m integration test_meeh.py
========================================================= test session starts =========================================================
platform darwin -- Python 3.6.4, pytest-3.1.2, py-1.5.2, pluggy-0.4.0
rootdir: /Users/yzT/Desktop, inifile:
collected 2 items

test_meeh.py F

============================================================== FAILURES ===============================================================
_________________________________________________________ test_meh[stability] _________________________________________________________

type = 'stability'

    @pytest.mark.parametrize('type',(
        pytest.param('stability', marks=pytest.mark.stability),
        pytest.param('integration', marks=pytest.mark.integration),
    ))
    @pytest.mark.integration
    @pytest.mark.stability
    def test_meh(type):
>       assert type == 'integration'
E       AssertionError: assert 'stability' == 'integration'
E         - stability
E         + integration

test_meeh.py:10: AssertionError
========================================================= 1 tests deselected ==========================================================
=============================================== 1 failed, 1 deselected in 0.07 seconds ================================================


$ pytest -m stability test_meeh.py
========================================================= test session starts =========================================================
platform darwin -- Python 3.6.4, pytest-3.1.2, py-1.5.2, pluggy-0.4.0
rootdir: /Users/yzT/Desktop, inifile:
collected 2 items

test_meeh.py .

========================================================= 1 tests deselected ==========================================================
=============================================== 1 passed, 1 deselected in 0.02 seconds ================================================

这是怎么回事？为什么当我使用 -m integration 它使用 stability 而当我使用 -m stability 它使用 integration ？

Answer 1

您提供的代码示例似乎有两个问题。

首先，您不应该同时标记单独的参数化测试和测试函数。只要您提供的 -m 选项与函数上的标记装饰器匹配，就会选择测试。

这是一个简单的比较。结合功能上的标记和单独的参数化测试:

# parametrized_tests.py
import pytest
@pytest.mark.parametrize('smiley', [
    pytest.param(':)', marks=[pytest.mark.happy]),
    pytest.param(':(', marks=[pytest.mark.unhappy]),
])
@pytest.mark.happy
@pytest.mark.unhappy
def test_meh(smiley):
    assert smiley == ':)'

您将收集并选择两个测试:

$ pytest -m happy --collect-only parametrized_tests.py
========================================================================================== test session starts ===========================================================================================
platform darwin -- Python 3.6.5, pytest-3.5.1, py-1.5.3, pluggy-0.6.0
rootdir: [redacted], inifile:
collected 2 items
<Module 'params-individual-tests.py'>
  <Function 'test_smiley[:)]'>
  <Function 'test_smiley[:(]'>

====================================================================================== no tests ran in 0.01 seconds ======================================================================================

但是如果只标记参数化测试:

# parametrized_tests.py
import pytest

@pytest.mark.parametrize('smiley', [
    pytest.param(':)', marks=[pytest.mark.happy]),
    pytest.param(':(', marks=[pytest.mark.unhappy]),
])
def test_smiley(smiley):
    assert smiley == ':)'

如您所料，您将收集到两个测试，但只选择了一个:

$ pytest -m happy --collect-only parametrized_tests.py
========================================================================================== test session starts ===========================================================================================
platform darwin -- Python 3.6.5, pytest-3.5.1, py-1.5.3, pluggy-0.6.0
rootdir: [redacted], inifile:
collected 2 items / 1 deselected
<Module 'params-individual-tests.py'>
  <Function 'test_smiley[:)]'>

====================================================================================== 1 deselected in 0.01 seconds ======================================================================================

其次，pytest.param 中似乎有一个令人费解的错误(或未记录的“功能”) ，其中使用标记的确切名称作为参数值会使测试未被选中。

来自您的(稍作修改的)代码:

# mark_name.py
import pytest

@pytest.mark.parametrize('type_', [
    pytest.param('integration', marks=[pytest.mark.integration]),
    pytest.param('stability', marks=[pytest.mark.stability]),
])
def test_meh(type_):
    assert type_ == 'integration'

如果我尝试只运行 integration 测试，它不会选择任何:

$ pytest -m integration mark_name.py
========================================================================================== test session starts ===========================================================================================
platform darwin -- Python 3.6.5, pytest-3.5.1, py-1.5.3, pluggy-0.6.0
rootdir: [redacted], inifile:
collected 2 items / 2 deselected

但只需修改值(在本例中我只将其设为大写)即可使一切按预期工作:

# mark_name.py
import pytest

@pytest.mark.parametrize('type_', [
    pytest.param('INTEGRATION', marks=[pytest.mark.integration]),
    pytest.param('STABILITY', marks=[pytest.mark.stability]),
])
def test_meh(type_):
    assert type_ == 'INTEGRATION'

现在我可以正确选择测试了:

$ pytest -m integration mark_name.py
========================================================================================== test session starts ===========================================================================================
platform darwin -- Python 3.6.5, pytest-3.5.1, py-1.5.3, pluggy-0.6.0
rootdir: [redacted], inifile:
collected 2 items / 1 deselected

mark_name.py .                                                                                                                                                                                     [100%]

================================================================================= 1 passed, 1 deselected in 0.01 seconds =================================================================================
$ pytest -m stability mark_name.py
========================================================================================== test session starts ===========================================================================================
platform darwin -- Python 3.6.5, pytest-3.5.1, py-1.5.3, pluggy-0.6.0
rootdir: [redacted], inifile:
collected 2 items / 1 deselected

mark_name.py F                                                                                                                                                                                     [100%]

================================================================================================ FAILURES ================================================================================================
__________________________________________________________________________________________ test_meh[STABILITY] ___________________________________________________________________________________________

type_ = 'STABILITY'

    @pytest.mark.parametrize('type_', [
        pytest.param('INTEGRATION', marks=[pytest.mark.integration]),
        pytest.param('STABILITY', marks=[pytest.mark.stability]),
    ])
    def test_meh(type_):
>       assert type_ == 'INTEGRATION'
E       AssertionError: assert 'STABILITY' == 'INTEGRATION'
E         - STABILITY
E         + INTEGRATION

mark_name.py:9: AssertionError
================================================================================= 1 failed, 1 deselected in 0.08 seconds =================================================================================

我怀疑这与用作测试 ID 的字符串值有关，但建议打开 GitHub issue如果这是您不想解决的问题。

---

此外，完全不相关，但最好不要将参数定义为 type，因为您正在隐藏内置函数 type . PEP-8建议使用尾部下划线来防止名称冲突。