self = <test_array_coercion.TestStringDiscovery object at 0x1a16d2f95dd0>
obj = 1.2

    @pytest.mark.parametrize("obj",
            [object(), 1.2, 10**43, None, "string"],
            ids=["object", "1.2", "10**43", "None", "string"])
    def test_nested_arrays_stringlength(self, obj):
        length = len(str(obj))
        expected = np.dtype(f"S{length}")
        arr = np.array(obj, dtype="O")
>       assert np.array([arr, arr], dtype="S").dtype == expected
E       RuntimeWarning: invalid value encountered in cast

arr        = array(1.2, dtype=object)
expected   = dtype('S3')
length     = 3
obj        = 1.2
self       = <test_array_coercion.TestStringDiscovery object at 0x1a16d2f95dd0>

../.venv/lib/python3.11/site-packages/numpy/_core/tests/test_array_coercion.py:180: RuntimeWarning