It seems not because the csv is a recarray, not a path to a downloaded file:

<pre>
>>> print mock.urls
set(['file:///home/virgile/nilearn/nilearn/tests/data/archive_dartel.tgz',
     'file:///home/virgile/nilearn/nilearn/tests/data/data_usage_agreement.txt',
     'file:///home/virgile/nilearn/nilearn/tests/data/archive.tgz'])
</pre>

`len(mock.urls)` should however be asserted being equal to 2 at line 344.