Question: Can callable as argument to ids parameter of parametrize of operate on a tuple?

[vreuter]

Using Python 2.7.12 and pytest 3.0.6

Sometimes I parameterize test cases with arguments via argvalues=itertools.product(..., ..., etc.). I'd like to be able to label the parameterized test cases but treat each argument a bit differently based on type. From the parametrize docstring, I was a bit confused whether the intent was to have the callable operate on a single element of an argval tuple, or the entire tuple. Just anecdotally, it seems like the ids customization is operating on one element of the argument value tuple rather than on the entire tuple, prohibiting the position-(type-)dependent behavior that I'd like when using a callable as the argument to ids. I can work around this by putting some type-indicative conditional logic in the callable that I pass to operate on a single tuple element, or just build up a list of string ids instead, but I'd like a cleaner callable route if possible. I'm wondering if I'm making a mistake in how I'm using this feature, or whether this is something that isn't currently supported.

import itertools
import pytest


def df1():
    return

def df2():
    return


@pytest.mark.parametrize(argnames="func,text",
                         argvalues=itertools.product([df1, df2],
                                                     ["first", "second"]),
                         ids=lambda args: "{}:{}".format(args[0].__name__,
                                                         args[1]))
def test_ids(func, text):
    pass

[RonnyPfannschmidt]

are you aware that multiple parametrize marks do the product on their own?

[vreuter]

Ah, excellent! Hadn't tried that, thanks.

[RonnyPfannschmidt]

i.e.

import itertools
import pytest


def df1():
    return

def df2():
    return


@pytest.mark.parametrize('func', [df1, df2])
@pytest.mark.parametrize('text', ["first", "second"])
def test_ids(func, text):
    pass

if i recall correct, py.test even manages the names correctly then on its own