marker transfer incompatible with inheritance

[pytestbot]

Originally reported by: Ronny Pfannschmidt (BitBucket: RonnyPfannschmidt, GitHub: RonnyPfannschmidt)

---

when a method is inherited, markers will trasnfer from the subclass to the superclass

#!python


import pytest

class TestAClass(object):

    def test_something(self):
        assert True

@pytest.mark.skipif("True")
class TestBClass(TestAClass):
    pass

class TestCClass(TestAClass):
    pass

will skip in TestCClass (given by tradej on irc)

im not yet sure if there is a clear backward-compatible way to solve this

---

• Bitbucket: https://bitbucket.org/pytest-dev/pytest/issue/535

[pytestbot]

Original comment by BitBucket: tgoodlet, GitHub: tgoodlet:

---

This is particularly painful with the pytest.mark.usefixtures decorator when sibling classes require mutually exclusive dependencies.
I was wondering why would fixing this problem affect backwards compat? Isn't this just simply incorrect?
What use case would leverage this?

[pytestbot]

Original comment by BitBucket: tgoodlet, GitHub: tgoodlet:

---

After a decent adventure into the source I've found the guilty method to be _pytest.python.PyCollector.collect() for Instance nodes:

https://bitbucket.org/hpk42/pytest/src/1189057a5a525222c98ceaf8d91a3e9614316409/_pytest/python.py?at=default#cl-317

The test function which is actually passed to self.makeitem(name, obj) is that from the parent class definition (i.e. self.obj.__class__.__dict__) and not the current instance (i.e. self.obj).
So the callable is actually the class function definition not the unbound class method or current instance method.
Addtionally, there is an underlying check in the _pytest.python.py: pytest_pycollect_makeitem hook namely, inspect.isfunction(obj) here:
https://bitbucket.org/hpk42/pytest/src/1189057a5a525222c98ceaf8d91a3e9614316409/_pytest/python.py?at=default#cl-227

This prevents modifcation of this method to simply call makeitem on the instance method...
I assume there is/was a good reason for this?
Can anyone comment on why this restriction is in place?
Also what was the original motivation behind not using the instance method directly?

[RonnyPfannschmidt]

fixed in #3317