Ruby on Rails

I am porting some Rails 4 code to Rails 5 and I hit the following problem when using  Rspec:  articles_index_path  is undefined.

routes.rb
Rails.application.routes.draw do
 devise_for :users
 root 'static_pages#root'
 resources :users

 resources :articles
 root to: "articles#index"
 # byebug
end


In /home/real-estate-data-mining/spec/requests/article_spec.rb I have
require 'rails_helper'
RSpec.describe "Article", type: :request do
 describe "GET /article" do
   it "works! (now write some real specs)" do
     byebug
     # get article_index_path
     get articles_index_path
     expect(response).to have_http_status(200)
   end
 end
end

When I examine the code environment around the byebug I see
[3, 12] in /home/real-estate-data-mining/spec/requests/article_spec.rb
   3: RSpec.describe "Article", type: :request do
   4:   describe "GET /article" do
   5:     it "works! (now write some real specs)" do
   6:       byebug
   7:       # get article_index_path
=>  8:       get articles_index_path
   9:       expect(response).to have_http_status(200)
  10:     end
  11:   end
  12: end
(byebug) articles_path
"/articles"
(byebug) articles_index_path
*** NameError Exception: undefined local variable or method `articles_index_path' for #<RSpec::ExampleGroups::Article_2::GETArticle:0x00563031a8a0e0>

nil
(byebug) article_index_path
*** NameError Exception: undefined local variable or method `article_index_path' for #<RSpec::ExampleGroups::Article_2::GETArticle:0x00563031a8a0e0>

nil
(byebug)



This must be a common software pattern in Rails but, damn, I have Googled for what feels like a googol (it's not a typo) hours without success trying to find what metaprogramming code would generate articles_index_path .