minitest-rails "Unable to resolve controller"

arcticles_controller.rb

class ArticlesController < ApplicationController

  def index
    render nothing: true
  end

end

articles_controller_test.rb

require 'test_helper'

class ArticlesControllerTest < ActionController::TestCase

  describe 'GET #index' do

    setup { get :index }

    it "does x" do
      assert true
    end

    it "does y" do
      assert true
    end

  end

end

result

 rake test TEST=test/controllers/articles_controller_test.rb     
Run options: --seed 60196

# Running:

EE

Finished in 0.085434s, 23.4099 runs/s, 0.0000 assertions/s.

  1) Error:
GET #index#test_0001_does x:
NameError: Unable to resolve controller for GET #index
    


  2) Error:
GET #index#test_0002_does y:
NameError: Unable to resolve controller for GET #index
    

2 runs, 0 assertions, 0 failures, 2 errors, 0 skips

test_helper.rb

ENV['RAILS_ENV'] ||= 'test'
require File.expand_path('../../config/environment', __FILE__)
require 'rails/test_help'
require 'minitest/rails'
require "minitest/rails/capybara"
require 'mocha/mini_test'

class ActiveSupport::TestCase
  fixtures :all
end

Does the following work?

require 'test_helper'

describe ArticlesController do
  it 'GETs #index' do
    get :index
    assert true
  end
end

in my case, the problem was require "minitest/rails/capybara"