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

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

Author: jakevdp

array_api_tests/test_searching_functions.py

@@ -87,14 +87,17 @@ def test_argmin(x, data):
         ph.assert_scalar_equals("argmin", type_=int, idx=out_idx, out=min_i, expected=expected)
 
 
+@given(xps.arrays(dtype=xps.scalar_dtypes(), shape=hh.shapes(min_dims=0, max_dims=0)))
+def test_nonzero_zerodim_error(x):
+    with pytest.raises(Exception):
+        xp.nonzero(x)
+
+
 @pytest.mark.data_dependent_shapes
-@given(xps.arrays(dtype=xps.scalar_dtypes(), shape=hh.shapes(min_side=1)))
+@given(xps.arrays(dtype=xps.scalar_dtypes(), shape=hh.shapes(min_dims=1, min_side=1)))
 def test_nonzero(x):
     out = xp.nonzero(x)
-    if x.ndim == 0:
-        assert len(out) == 1, f"{len(out)=}, but should be 1 for 0-dimensional arrays"
-    else:
-        assert len(out) == x.ndim, f"{len(out)=}, but should be {x.ndim=}"
+    assert len(out) == x.ndim, f"{len(out)=}, but should be {x.ndim=}"
     out_size = math.prod(out[0].shape)
     for i in range(len(out)):
         assert out[i].ndim == 1, f"out[{i}].ndim={x.ndim}, but should be 1"

numpy-skips.txt

@@ -21,6 +21,9 @@ array_api_tests/test_array_object.py::test_getitem
 # missing copy arg
 array_api_tests/test_signatures.py::test_func_signature[reshape]
 
+# does not (yet) raise an exception for zero-dimensional inputs to nonzero
+array_api_tests/test_searching_functions.py::test_nonzero_zerodim_error
+
 # https://github.com/numpy/numpy/issues/21211
 array_api_tests/test_special_cases.py::test_iop[__iadd__(x1_i is -0 and x2_i is -0) -> -0]
 # https://github.com/numpy/numpy/issues/21213