RSpec with Anonymous controller

rspec_with_anonymous_controller.rb

require 'rails_helper'

RSpec.describe V1::BaseController, :type => :controller do

  before do
    Rails.application.routes.draw do
      match "/v1/dummy", to: "v1/base#index", via: :all
    end
  end

  after do
    Rails.application.reload_routes!
  end

  controller do
    def index
      render json: { success: true }
    end
  end
  
  it "should succeed" do
    get :index
    expect(response).to be_success
  end
  
end