Different interaction between fixtures, functools.wraps and default arguments in python 2 and 3

[pytestbot]

Originally reported by: David MacIver (BitBucket: david_maciver_, GitHub: david_maciver_)

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#!python

from functools import wraps


def add_default(f):
    @wraps(f)
    def hello(x=1):
        return f(x)
    return hello


@add_default
def test_hello(x):
    assert x == 1

In python 2 the addition of the default works: The test is called with x=1. In python 3 this looks for a fixture and errors with fixture 'x' not found.

Additionally, if I remove the wraps this works in both versions.

I'm not sure what the intended correct behaviour is, but having the behaviour be different between 2 or 3 sounds like a bug regardless of which one is correct.

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• Bitbucket: https://bitbucket.org/pytest-dev/pytest/issue/677

[RonnyPfannschmidt]

python3 is correct, python2 has a bug in functools.wraps

@DRMacIver where you the reporter?

[DRMacIver]

Yep, that was me. I'm no longer directly affected by this issue because I have a huge elaborate function wrapping infrastructure to work around it and some related things now. :-)

[Zearin]

Yep, that was me. I'm no longer directly affected by this issue because I have a huge elaborate function wrapping infrastructure to work around it and some related things now. :-)

Would you be willing to link to your elaborate function wrapping infrastructure? Perhaps it could help the devs fix this bug. :)

[RonnyPfannschmidt]

closing this one as user code bug, python2 has a broken functools.wraps