Description

On latest release and also on master branch, windows 10

The following test:

from numpy import linspace from pytest import fixture @fixture(params=linspace(1, 10, 10)) def value(request): return request.param def test_bug(value): assert value == value

breaks with:

Traceback (most recent call last): File "D:/WORK/pytest-nparray-params-bug/test_bug.py", line 4, in <module> @fixture(params=linspace(1, 10, 10)) File "D:\WORK\pytest-nparray-params-bug\venv\lib\site-packages\_pytest\fixtures.py", line 1123, in fixture name=name File "D:\WORK\pytest-nparray-params-bug\venv\lib\site-packages\_pytest\fixtures.py", line 1032, in _parse_fixture_args key: value for key, value in kwargs.items() if arguments.get(key) != value File "D:\WORK\pytest-nparray-params-bug\venv\lib\site-packages\_pytest\fixtures.py", line 1032, in <dictcomp> key: value for key, value in kwargs.items() if arguments.get(key) != value ValueError: The truth value of an array with more than one element is ambiguous. Use a.any() or a.all()

Cause

It seems that this line:

Tries to get a boolean result from comparing None != <array> which is ambiguous.

Possible solution

This might be solved by moving the cast to list (line 1137) at the very beginning (1116) of this function:

I am actually running tests with this change but not 100% certain about side-effects, although it seems to be that casting to list that soon should not cause problems (equivalent of casting to list in user test code).

If you think this is okay I can create the PR.

• a detailed description of the bug or suggestion
• output of pip list from the virtual environment you are using
• pytest and operating system versions
• minimal example if possible