如何以交互方式获得pytest fixture？

如何导入或以其他方式绑定pytest fixture以便交互使用,而不使用断点？

例如,我想探索REPL中tmpdir_factory夹具的一些行为.

from pytest import tmpdir_factory  # note: this doesn't actually work

# setup / context has already been entered
tmpdir_factory.ensure('exists.txt', file=True)  # I can use the fixture
del tmpdir_factory  # teardown will eventually be called

在tmpdir的情况下,我已经知道它只是一个py.path.local实例,但我也对用户定义的灯具的一般问题感兴趣.

编辑：另一个可接受的界面

from magical_module import inject_fixture
tmpdir_factory = inject_fixture('tmpdir_factory')

编辑：一个MCVE,用于显示上下文是否已退出：

# conftest.py
from datetime import datetime
import pytest

@pytest.fixture
def my_fixture():
    obj = {'setup': datetime.Now()}
    yield (obj, f'yielded @ {datetime.Now()!r}')
    obj['teardown'] = datetime.Now()

解决方法:

虽然某些灯具可在会话范围内使用,但在运行测试之前,任何灯具都不会获得值.使用fixture最简单的方法是在测试函数中设置一个断点……但是我们可以通过一些hackery来绕过它：

# magical_module.py
import pytest

_fixture_name = None
_fixture_value = None

def test_stuff(request):
    global _fixture_value
    fixturedef = request._get_active_fixturedef(_fixture_name)
    fixturedef._finalizer = []  # disable fixture teardown
    _fixture_value = fixturedef.cached_result[0]

def inject_fixture(fixturename):
    global _fixture_name
    _fixture_name = fixturename
    pytest.main(['-qq', __file__])
    return _fixture_value

然后您可以从REPL访问它们

$python
Python 3.6.2 (default, Jul 20 2017, 08:43:29) 
[GCC 5.4.1 20170519] on linux
Type "help", "copyright", "credits" or "license" for more @R_40_4045@ion.
>>> from magical_module import inject_fixture
>>> tmpdir_factory = inject_fixture('tmpdir_factory')
.
>>> tmpdir_factory
<_pytest.tmpdir.TempdirFactory object at 0x7fbf22df46a0>