Помогите с контроллером

  def create
    @url = encode_url(params[:url])
    uri = URI(@url)

    @host = Host.find_by_address(normalize_domain(uri.host))
    @resource = @host.resources.new(path: get_full_path(uri), csspaths: params[:csspaths], period: params[:period])

    if @resource.save
      redirect_to '/settings/resources', notice: 'Resource was saved.'
    else
      render :new
    end
  end

  let(:host) { mock_model(Host).as_null_object }

  before do
    Host.stub(:find).and_return(host)
  end

  it "should find @host" do
    Host.should_receive(:find_by_address).and_return(host)

    post :create, url: "opennet.ru"
  end

ResourcesController#create should find @host
     Failure/Error: post :create, url: "opennet.ru"
     NoMethodError:
       undefined method `sub' for nil:NilClass
     # ./app/controllers/application_controller.rb:22:in `normalize_domain'
     # ./app/controllers/resources_controller.rb:17:in `create'
     # ./spec/controllers/resources_controller_spec.rb:40:in `block (3 levels) in <top (required)>'