Make sure we treat tests differently

When using pytest fixtures, you are supposed to just declare them as input arguments, and they will be automagically loaded. For example:

import pytest
from myapp import meaning_of_life


@pytest.fixture
def foo():
    return 42

def test_meaning_of_life(foo):
    meaning = meaning_of_life()
    assert meaning == foo

This will violate rule 442, which is not desired in this case.

One could argue that fixtures should live on a different file than tests, but you run on the same issue if you have fixtures dependent on other fixtures:

import pytest


@pytest.fixture
def foo():
    return 42


@pytest.fixture
def bar(foo):
    return foo + 1

I think we need to make this feature “pytest aware”, or just document that it there is conflict with it and might need to be disabled.

[skarzi]

My per-file-ignores for tests includes violations mentioned by @sobolevn and additionally following one:

• WPS118 - imho test functions/methods should have nice, meaningful names, so it’s often better to use long but self-explanatory name for them

[sobolevn]

Might be related: #1268

Maybe we can use some kind of --tests-filename-pattern (similar to http://doc.pytest.org/en/latest/reference.html#confval-python_files)? And disable some checks there by default?

I don’t see much value in just updating the docs for this one. I suggest to add a feature that will solve this case.