monkeypatch'ing functools.partial causes INTERNALERROR #3288
Description
Hi,
I've got this test
import functools
from unittest.mock import Mock
def test_partial(monkeypatch):
monkeypatch.setattr(functools, "partial", Mock())
assert functools.partial.call_count == 1Running pytest on a clean environment produces:
INTERNALERROR> if isinstance(obj, functools.partial):
INTERNALERROR> TypeError: isinstance() arg 2 must be a type or tuple of types
I'm not sure if this kind of patching is supported.
Note that the error only happens if the assert causes the test to fail, otherwise everything works.
I'm using version 3.4.2
pip list:
attrs (17.4.0)
pip (9.0.1)
pkg-resources (0.0.0)
pluggy (0.6.0)
py (1.5.2)
pytest (3.4.2)
setuptools (38.5.2)
six (1.11.0)
wheel (0.30.0)
OS: Ubuntu 16.04.4 LTS
