error of redirect page (Controller Test)

Hi,

I have a trouble of testing controller with redirect to the confirm
page
I dont understand why i can pass the render the template new but not
to
redirect the confirm

please help

in browser the link is
http://0.0.0.0:3000/register_confirm

  def create
    @user = User.new(params[:user])
    if @user.save
      redirect_to :action => "confirm"
    else
      render "new"
    end
  end

Test file

  it "should save redirect to confirm" do
       User.any_instance.stubs(:valid?).returns(true)
       post 'create'
       assigns[:user].should_not be_new_record
   response.should redirect_to('confirm')
    end

        it "should not save redirect to new" do
       User.any_instance.stubs(:valid?).returns(false)
       post 'create'
       assigns[:user].should be_new_record
  response.should render_template('new')
    end

error

  1) UsersController GET create should save redirect to confirm
     Failure/Error: response.should redirect_to('confirm')
       Expected response to be a <:redirect>, but was <200>.
       Expected block to return true value.