AppController.rb

class ApplicationController < ActionController::Base
  protect_from_forgery
  
  helper_method :is_manager?, :current_cart, :cc
  
  
  protected
  def current_cart
    @current_cart ||= session[:cart_key] ? Cart.where(w).first : Cart.new
  end
end

CartsControllerTest.rb

    #how do I setup the @cart variable if the correct call for it is in the ApplicationController?



require 'test_helper'

class CartsControllerTest < ActionController::TestCase
  setup do
    @cart = carts(:one)

    # ???????????

  end

  test "should get index" do
    get :index
    assert_response :success
    assert_not_nil assigns(:carts)
  end
  
  test "should show cart" do
    get :show, :id => :current
    assert_response :success
  end

  test "should update cart" do
    put :update, :id => :current, :cart => @cart.attributes
    assert_redirected_to cart_path(assigns(:cart))
  end