[aaronkanzer]

Indexing a multidimensional NXfield with ... or None (np.newaxis) raises an error, whether the field is in memory or loaded from a file.

import numpy as np
from nexusformat.nexus import NXfield

x = NXfield(np.arange(20).reshape(4, 5))
x[..., -1]

Observed: NeXusError: NXfield must be one-dimensional for floating point slices. x[0, ...], x[None, 0] and x[:, None] fail the same way.

Expected: [4 9 14 19], the same as NumPy.

Cause: is_real_slice checks each index element with np.array(x).dtype. np.array(Ellipsis) and np.array(None) are object arrays, so they count as real values, and convert_index then rejects the 2D field.

Fix: return False for Ellipsis and None in the inner is_real check. A parametrized test covers ... and np.newaxis on 2D and 3D fields.