first draft for a simple hooks based custom attribute storage, with a BytesFileSystemStorage POC implementation. Basically: * a dictionary contains maps from which attribute of which entity types are mapped to which custom storage * hooks check for one of these entity type being added/modified/deleted * read is based on the sql generator callback mecanism (used in vcsfile for instance) * all storages have the same basic interface (read, add, update, delete), and should be pluggable in a transparent way (except at migration time when one want to change from a storage to another) * the sample BytesFileSystemStorage: * may store Bytes attributes content of any entity type as file on the file system * is based on one FSPATH rql/sql function and another _fsopen only available in sql * has a dumb file name allocation algorithm

"""this pytestconf automatically adds the mx's python version in the PYTHONPATH
:license: GNU Lesser General Public License, v2.1 - http://www.gnu.org/licenses
"""
import sys
import os.path as osp

import cubicweb
# remove 'mx' modules imported by cubicweb
for modname in sys.modules.keys():
    if modname.startswith('mx'):
        sys.modules.pop(modname)

# this is where mx should get imported from
mxpath = osp.abspath(osp.join(osp.dirname(cubicweb.__file__), 'embedded'))
sys.path.insert(1, mxpath)

# make sure the correct mx is imported
import mx
assert osp.dirname(mx.__file__) == osp.join(mxpath, 'mx'), '%s != %s' % (osp.dirname(mx.__file__), mxpath)