title: Why is my RSpec not loading Devise::Test::ControllerHelpers?
body: <p>I'm using Rails 5, and Devise 3.5.1.</p>
  
  <p>Going through a nice (older) book about creating/testing an API, which uses Devise authentication. It was written before Rails 5, so I chose not to use the new api-only version.</p>
  
  <p>Here's my test...</p>
  
  <pre><code>#/spec/controllers/api/v1/users_controller_spec.rb    
  
  require 'rails_helper'
  
  describe Api::V1::UsersController, :type =&gt; :controller do
      before(:each) { request.headers['Accept'] = "application/vnd.marketplace.v1" }
      describe "GET #show" do
          before(:each) do
              @user = FactoryGirl.create :user
              get :show, params: {id: @user.id}, format: :json
          end
          it "returns the information about a reporter on a hash" do
              user_response = JSON.parse(response.body, symbolize_names: true)
              expect(user_response[:email]).to eql @user.email
          end
          it { should respond_with 200 }
      end
  end
  </code></pre>
  
  <p>And here's a completely unexpected RSpec error</p>
  
  <pre><code>Devise::MissingWarden:
         Devise could not find the `Warden::Proxy` instance on your request environment.
         Make sure that your application is loading Devise and Warden as expected and that the `Warden::Manager` middleware is present in your middleware stack.
         If you are seeing this on one of your tests, ensure that your tests are either executing the Rails middleware stack or that your tests are using the `Devise::Test::ControllerHelpers` module to inject the `request.env['warden']` object for you.
  </code></pre>
  
  <p>So I go here - <a href="http://www.rubydoc.info/gems/devise/Devise/Test/ControllerHelpers">http://www.rubydoc.info/gems/devise/Devise/Test/ControllerHelpers</a></p>
  
  <p>and tried this -> <strong>include Devise::Test::ControllerHelpers</strong></p>
  
  <p>which didn't help because the file <code>controller_helpers.rb</code> is nowhere in my project</p>
  
  <p>What did I miss here?</p>
  
  <p>Thanks</p>