pytest-dev / pytest-dev/pytest-flask
PicklingError using live_server fixture on Windows
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bug
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- Dominant language
- Python
- Stars
- 499
- Forks
- 93
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Description
Not sure if Windows is supposed to be supported, but for me it fails on Windows 10 Python 2.7.12 with the following error when live_server fixture used:
request = <SubRequest '_push_request_context' for <Function 'test_get_url'>>
@pytest.fixture(autouse=True)
def _push_request_context(request):
"""During tests execution request context has been pushed, e.g. `url_for`,
`session`, etc. can be used in tests as is::
def test_app(app, client):
assert client.get(url_for('myview')).status_code == 200
"""
if 'app' not in request.fixturenames:
return
app = request.getfuncargvalue('app')
# Get application bound to the live server if ``live_server`` fixture
# is applyed. Live server application has an explicit ``SERVER_NAME``,
# so ``url_for`` function generates a complete URL for endpoint which
# includes application port as well.
if 'live_server' in request.fixturenames:
> app = request.getfuncargvalue('live_server').app
..\..\..\..\python-virtualenv\shadow\Lib\site-packages\pytest_flask\plugin.py:85:
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
..\..\..\..\python-virtualenv\shadow\Lib\site-packages\pytest_flask\fixtures.py:127: in live_server
server.start()
..\..\..\..\python-virtualenv\shadow\Lib\site-packages\pytest_flask\fixtures.py:64: in start
self._process.start()
c:\python27\Lib\multiprocessing\process.py:130: in start
self._popen = Popen(self)
c:\python27\Lib\multiprocessing\forking.py:277: in __init__
dump(process_obj, to_child, HIGHEST_PROTOCOL)
c:\python27\Lib\multiprocessing\forking.py:199: in dump
ForkingPickler(file, protocol).dump(obj)
c:\python27\Lib\pickle.py:224: in dump
self.save(obj)
c:\python27\Lib\pickle.py:331: in save
self.save_reduce(obj=obj, *rv)
c:\python27\Lib\pickle.py:425: in save_reduce
save(state)
c:\python27\Lib\pickle.py:286: in save
f(self, obj) # Call unbound method with explicit self
c:\python27\Lib\pickle.py:655: in save_dict
self._batch_setitems(obj.iteritems())
c:\python27\Lib\pickle.py:687: in _batch_setitems
save(v)
c:\python27\Lib\pickle.py:286: in save
f(self, obj) # Call unbound method with explicit self
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
self = <multiprocessing.forking.ForkingPickler instance at 0x0000000007EDBA08>
obj = <function <lambda> at 0x00000000081B9DD8>, name = '<lambda>'
pack = <built-in function pack>
def save_global(self, obj, name=None, pack=struct.pack):
write = self.write
memo = self.memo
if name is None:
name = obj.__name__
module = getattr(obj, "__module__", None)
if module is None:
module = whichmodule(obj, name)
try:
__import__(module)
mod = sys.modules[module]
klass = getattr(mod, name)
except (ImportError, KeyError, AttributeError):
raise PicklingError(
"Can't pickle %r: it's not found as %s.%s" %
> (obj, module, name))
E PicklingError: Can't pickle <function <lambda> at 0x00000000081B9DD8>: it's not found as pytest_flask.fixtures.<lambda>
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Start by reproducing the live_server fixture failure on Windows with Python 2.7.12, then inspect pytest_flask/plugin.py around line 85 and pytest_flask/fixtures.py around lines 64 and 127. Trace the multiprocessing startup that raises PicklingError and establish whether the expected result is a working live_server fixture or a documented Windows support limitation.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- flask, python
- Domain
- testing
- Issue type
- Bug
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Stale
- Clarity
- Needs clarification
- Newbie friendliness
- 30/100