ksubramz/nibabel-1 — comment on commit 2655aec5d50bffb8f3c5cfb341c9324dada060fc
File: nibabel/freesurfer/tests/test_mgh_io.py line 47
By matthew-brett:

You need a real temporary file - we can't guarantee our data directory is writable in general.

See the 'InTemporaryDirectory' context manager in nibabel/tmpdirs for one easy way.