thanks I'll ... I found the issue ...
moving to the form into a modal window, I was using a duplicated (and
renamed) copy of _expense_fields.html.haml partial
and I was testing in with this copy ...
obviously the = link_to_add_association f, :expenses is using the
initial partial .... _expense_fields.html.haml
so all my tests were bypassed ...
On Mar 21, 5:42 pm, Carlos Antonio da Silva