Trouble testing for page element

I'm trying to use Luke Redpath's hpricot_test_helper plugin to test for
the existence of a page element in my integration test. I get errors
like "nil.content_for" for even when using examples copied directly from
his tutorial which indicate that the @output variable in
hpricot_test_helper is coming up nil:

  def tag(css_query)
    @output.content_for(css_query)
  end

I thought the plugin be configured to receive html output upon
installation via hpricot. Am I mistaken?

Also, are people still using this? At 18th months old it's somewhat
dated by rails standards. Is there something later and greater I should
be using?

Thanks,

Peter