helpers.rb

module Helpers
  def sign_in(user)
    @user_session = UserSession.create user
  end
  
  def fill_in_autocomplete(selector, value)
    page.execute_script %Q{$('#{selector}').val('#{value}').keydown()}
  end

  def choose_autocomplete(text)
    find('ul.ui-autocomplete').should have_content(text)
    page.execute_script("$('.ui-menu-item:contains(\"#{text}\")').find('a').trigger('mouseenter').click()")
  end
  
  def wait_for_animation
    wait_until do
      page.evaluate_script('$(":animated").length') == 0
    end
  end
end

register_spec.rb

# Here's how to use the autocomplete, and how to avoid triggering the autocomplete.

  context "User chooses new company" do
    before(:each) do
      visit new_user_path
      fill_in_autocomplete "#user_dealership_attributes_company_attributes_name", "New company"
      choose_autocomplete "New Company"
      wait_for_animation
    end
    
    it "should expose new company and dealership fields" do
      page.find(".company_info_fields").should be_visible
      page.find("#new_dealership_fields").should be_visible
    end
  end
  
  context "User does not use autocomplete" do
    it "should expose new company and dealership fields" do
      visit new_user_path
      page.execute_script %Q{$("#user_dealership_attributes_company_attributes_name").val("New company").change()}
      wait_for_animation
      page.find(".company_info_fields").should be_visible
      page.find("#new_dealership_fields").should be_visible
    end
  end