Committing a record update to the DB from a test

Hi all, I hope someone can help me with this.

I'm trying to write a test to see if my versioning (acts_as_versioned)
works. In order to do that, I have a class which inherits from
ActiveRecord:
class Order < ActiveRecord::Base

However, when I try to update or to create a new order within the
test, my changes do not affect the DB:
    o = Order.create(:name => 'n', :email => 'e', :address =>
'a', :pay_type => 'po')
    o.save
    o.name = 'm'
    o.save
    order = Order.find(@first_id)
    #order.pay_type = 'po'; order.address = 'dummy address';
order.email = 'd@d.d'; order.name = 'first ammended'
    order.update_attributes({ :pay_type => 'po', :address => '123 hh
road', :email => 'r@r.r', :name => '2nd ammended'})

I run this, and nothing is committed to the DB! Can anyone help?

Thanks