With PYTHONHASHSEED=0, editing a document like this:

    foo.edit(
      title="live_test_%s" % new_id,
      reference="live_test_%s" % new_id
    )

only sets the reference, because it sets the reference first and then
when setting title it already has the "live_test_%s" % new_id value (
because title is acquired from reference).

With PYTHONHASHSEED set, the order is not guaranteed and sometimes
title is edited before reference. This is revealed by
testHalJsonStyle.TestERP5Document_getHateoas_mode_search with
PYTHONHASHSEED 465.