Test that nonzero on zero-dimensional array raises an exception.

[jakevdp]

This is required by the spec. From https://data-apis.org/array-api/2022.12/API_specification/generated/array_api.nonzero.html:

Parameters
x (array) – input array. Must have a positive rank. If x is zero-dimensional, the function must raise an exception.

I made this a separate test so that implementations can mark it to skip if desired (this currently raises a DeprecationWarning in NumPy, but will error in a future release).

[honno]

Nice catch thanks! LGTM.

Historically I've tested errors all in the same function to keep with some platonic ideal of 1 "primary test" per function, e.g.

array-api-tests/array_api_tests/test_manipulation_functions.py

Lines 131 to 135 in d58fb6b

	def test_expand_dims(x, axis):
	if axis < -x.ndim - 1 or axis > x.ndim:
	with pytest.raises(IndexError):
	xp.expand_dims(x, axis=axis)
	return

which I'm not sure is worth it or that practical for either us maintaining array-api-tests or adopting libraries all the time. In any case, having a separate test makes sense here for sure.

[jakevdp]

Thanks!