python - 将(产量)装置作为测试参数传递(使用临时目录)

Question

问题

是否可以将 yielding pytest fixtures(用于设置和拆卸)作为参数传递给测试函数？

上下文

我正在测试一个对象，该对象从单个目录中的文件读取数据/向文件写入数据。该目录的路径被保存为对象的属性。

我遇到以下问题:

1. 在我的测试中使用一个临时目录；和
2. 确保在每次测试后删除该目录。

例子

考虑以下 (test_yieldfixtures.py):

import pytest, tempfile, os, shutil
from contextlib import contextmanager
    
@contextmanager
def data():
    datadir = tempfile.mkdtemp()  # setup
    yield datadir
    shutil.rmtree(datadir)        # teardown
    
class Thing:
    def __init__(self, datadir, errorfile):
        self.datadir = datadir
        self.errorfile = errorfile

    
@pytest.fixture
def thing1():
    with data() as datadir:
        errorfile = os.path.join(datadir, 'testlog1.log')
        yield Thing(datadir=datadir, errorfile=errorfile)

@pytest.fixture
def thing2():
    with data() as datadir:
        errorfile = os.path.join(datadir, 'testlog2.log')
        yield Thing(datadir=datadir, errorfile=errorfile)

@pytest.mark.parametrize('thing', [thing1, thing2])
def test_attr(thing):
    print(thing.datadir)
    assert os.path.exists(thing.datadir)

运行 pytest test_yieldfixtures.py 输出如下:

================================== FAILURES ===================================
______________________________ test_attr[thing0] ______________________________

thing = <generator object thing1 at 0x0000017B50C61BF8>

    @pytest.mark.parametrize('thing', [thing1, thing2])
    def test_attr(thing):
>        print(thing.datadir)
E       AttributeError: 'function' object has no attribute 'props'

test_mod.py:39: AttributeError

好的。所以 fixture 函数没有我的类的属性。很公平。

尝试 1

函数没有属性，所以我尝试调用该函数来实际获取对象。然而，那只是

@pytest.mark.parametrize('thing', [thing1(), thing2()])
def test_attr(thing):
    print(thing.props['datadir'])
    assert os.path.exists(thing.get('datadir'))

结果:

================================== FAILURES ===================================
______________________________ test_attr[thing0] ______________________________

thing = <generator object thing1 at 0x0000017B50C61BF8>

    @pytest.mark.parametrize('thing', [thing1(), thing2()])
    def test_attr(thing):
>       print(thing.datadir)
E       AttributeError: 'generator' object has no attribute 'props'

test_mod.py:39: AttributeError

尝试 2

我还尝试在 thing1/2 固定装置中使用 return 而不是 yield ，但这使我退出了 data 上下文管理器并删除目录:

================================== FAILURES ===================================
______________________________ test_attr[thing0] ______________________________

thing = <test_mod.Thing object at 0x000001C528F05358>

    @pytest.mark.parametrize('thing', [thing1(), thing2()])
    def test_attr(thing):
        print(thing.datadir)
>       assert os.path.exists(thing.datadir)

结束语

重述问题:是否有办法将这些固定装置作为参数传递并保持临时目录的清理？

Answer 1

尝试将您的data 函数/生成器制作成固定装置。然后使用 request.getfixturevalue()动态运行命名的 fixture 。

import pytest, tempfile, os, shutil
from contextlib import contextmanager

@pytest.fixture # This works with pytest>3.0, on pytest<3.0 use yield_fixture
def datadir():
    datadir = tempfile.mkdtemp()  # setup
    yield datadir
    shutil.rmtree(datadir)        # teardown

class Thing:
    def __init__(self, datadir, errorfile):
        self.datadir = datadir
        self.errorfile = errorfile


@pytest.fixture
def thing1(datadir):
    errorfile = os.path.join(datadir, 'testlog1.log')
    yield Thing(datadir=datadir, errorfile=errorfile)

@pytest.fixture
def thing2(datadir):
    errorfile = os.path.join(datadir, 'testlog2.log')
    yield Thing(datadir=datadir, errorfile=errorfile)

@pytest.mark.parametrize('thing_fixture_name', ['thing1', 'thing2'])
def test_attr(request, thing):
    thing = request.getfixturevalue(thing) # This works with pytest>3.0, on pytest<3.0 use getfuncargvalue
    print(thing.datadir)
    assert os.path.exists(thing.datadir)

更进一步，您可以像这样参数化thing fixtures:

class Thing:
    def __init__(self, datadir, errorfile):
        self.datadir = datadir
        self.errorfile = errorfile

@pytest.fixture(params=['test1.log', 'test2.log'])
def thing(request):
    with tempfile.TemporaryDirectory() as datadir:
        errorfile = os.path.join(datadir, request.param)
        yield Thing(datadir=datadir, errorfile=errorfile)

def test_thing_datadir(thing):
    assert os.path.exists(thing.datadir)