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Bug with parameterized classes when running tests twice #683
Description
Originally reported by: BitBucket: astrofrog, GitHub: astrofrog
If we consider the following example and place it in a file called test_double.py:
import pytest
class TestA(object):
pass
@pytest.mark.parametrize(('model_class'), [1,2,3])
class TestB(TestA):
def test_1(self, model_class):
pass
We can then try and run this with:
py.test test_double.py test_double.py
This produces the following error:
========================================================= test session starts ==========================================================
platform darwin -- Python 3.4.2 -- py-1.4.23 -- pytest-2.6.1
plugins: cov, xdist
collected 3 items / 1 errors
test_double.py ...
================================================================ ERRORS ================================================================
___________________________________________________ ERROR collecting test_double.py ____________________________________________________
../Library/Python/3.4/lib/python/site-packages/_pytest/runner.py:139: in __init__
self.result = func()
../Library/Python/3.4/lib/python/site-packages/_pytest/main.py:438: in _memocollect
return self._memoizedcall('_collected', lambda: list(self.collect()))
../Library/Python/3.4/lib/python/site-packages/_pytest/main.py:315: in _memoizedcall
res = function()
../Library/Python/3.4/lib/python/site-packages/_pytest/main.py:438: in <lambda>
return self._memoizedcall('_collected', lambda: list(self.collect()))
../Library/Python/3.4/lib/python/site-packages/_pytest/python.py:538: in collect
return super(Instance, self).collect()
../Library/Python/3.4/lib/python/site-packages/_pytest/python.py:333: in collect
res = self.makeitem(name, obj)
../Library/Python/3.4/lib/python/site-packages/_pytest/python.py:345: in makeitem
collector=self, name=name, obj=obj)
../Library/Python/3.4/lib/python/site-packages/_pytest/main.py:166: in call_matching_hooks
return hookmethod.pcall(plugins, **kwargs)
../Library/Python/3.4/lib/python/site-packages/_pytest/core.py:417: in pcall
return self._docall(methods, kwargs)
../Library/Python/3.4/lib/python/site-packages/_pytest/core.py:424: in _docall
res = mc.execute()
../Library/Python/3.4/lib/python/site-packages/_pytest/core.py:315: in execute
res = method(**kwargs)
../Library/Python/3.4/lib/python/site-packages/_pytest/python.py:236: in pytest_pycollect_makeitem
return list(collector._genfunctions(name, obj))
../Library/Python/3.4/lib/python/site-packages/_pytest/python.py:361: in _genfunctions
gentesthook.pcall(plugins, metafunc=metafunc)
../Library/Python/3.4/lib/python/site-packages/_pytest/core.py:417: in pcall
return self._docall(methods, kwargs)
../Library/Python/3.4/lib/python/site-packages/_pytest/core.py:424: in _docall
res = mc.execute()
../Library/Python/3.4/lib/python/site-packages/_pytest/core.py:315: in execute
res = method(**kwargs)
../Library/Python/3.4/lib/python/site-packages/_pytest/python.py:146: in pytest_generate_tests
metafunc.parametrize(*marker.args, **marker.kwargs)
../Library/Python/3.4/lib/python/site-packages/_pytest/python.py:836: in parametrize
param_index)
../Library/Python/3.4/lib/python/site-packages/_pytest/python.py:717: in setmulti
self._checkargnotcontained(arg)
../Library/Python/3.4/lib/python/site-packages/_pytest/python.py:700: in _checkargnotcontained
raise ValueError("duplicate %r" %(arg,))
E ValueError: duplicate 'model_class'
We discovered this because when running Astropy tests twice in a row:
import astropy
astropy.test()
astropy.test()
the same error occurs.
Activity
pytestbot commentedon Feb 16, 2015
Original comment by Erik Bray (BitBucket: embray, GitHub: embray):
Just poking around at this a bit, what I found is that in
PyCollector._genfunctionsthe routinetransfer_markers, which copies markers on classes onto their methods, every time the tests are run.I wonder if it would be possible to somehow "undo" this after the test run, perhaps by copying the test method's original
__dict__and then restoring it afterwards.Another possibility might be to have a reverse of
transfer_markers--it should be possible to unambiguously removing markers added to a test method from its class after it has been run.pytestbot commentedon Feb 16, 2015
Original comment by Erik Bray (BitBucket: embray, GitHub: embray):
Or perhaps more simply
transfer_markerscould just check for duplicates in the first place.Test file run twice fails if it contains marked class pytest-dev#683
Test file run twice fails if it contains marked class #683
Mention fix for issue #683
flub commentedon Jul 26, 2015
Fix from @ojake merged, thanks