Add support for dictionary `argvalues` for `parametrize`

[kevinjfoley]

I'd like to be able to pass a dictionary to pytest.mark.parametrize as argvalues with the keys as ids and the values as argvalues

For example:

import pytest


@pytest.mark.parametrize(["a", "b"], {"test 1": (1, 2), "test 2": (3, 4)})
def test_foo(a, b):

    assert a + 1 == b

# instead of
@pytest.mark.parametrize(["a", "b"], [(1, 2), (3, 4)], ids=["test 1", "test 2"])
def test_foo(a, b):

    assert a + 1 == b

would generate two tests named "test 1" and "test 2".

Before trying to add this feature I wanted to make sure there's no foreseen issues with a making change like this.

[asottile]

I'm -1

You can already do this which satisfies the same thing without creating more edge cases:

@pytest.mark.parametrize(["a", "b"], (pytest.param(1, 2, id='test 1'), pytest.param(3, 4, id='test 2')))

[kevinjfoley]

I completely missed that in the guide, using pytest.param does what I'm looking for. Thanks!

[blueyed]

I think using pytest.param is not really straight-forward, and less readable in general:

Currently:

@pytest.mark.parametrize(
    ["a", "b"], (
        pytest.param(1, 2, id='test 1'),
        pytest.param(3, 4, id='test 2'),
    )
)

New:

@pytest.mark.parametrize(
    ["a", "b"], {
        'test 1': (1, 2),
        'test 2': (3, 4),
    }
)

A workaround is of course to use a dict in the first place, and then use that,
but it would be better to not have this redirection also:

@pytest.mark.parametrize("a,b", t.values(), ids=list(t.keys())

It feels pretty natural to use a dict here, since the ID is supposed to be unique.

For reference: I've created https://github.com/blueyed/pytest-enhancements, which includes this.