[dangotbanned]

Originally added in e1290d4

Trying to reduce the size of #3631.
This change is atomic and useful enough on its own.

Example

altair/tests/test_datasets.py

Lines 52 to 71 in 7d6b81d

	requires_pyarrow: pytest.MarkDecorator = skip_requires_pyarrow()
	backends: pytest.MarkDecorator = pytest.mark.parametrize(
	"backend",
	[
	"polars",
	pytest.param(
	"pandas",
	marks=pytest.mark.xfail(
	find_spec("pyarrow") is None,
	reason=(
	"`pandas` supports backends other than `pyarrow` for `.parquet`.\n"
	"However, none of these are currently an `altair` dependency."
	),
	),
	),
	pytest.param("pandas[pyarrow]", marks=requires_pyarrow),
	pytest.param("pyarrow", marks=requires_pyarrow),
	],
	)