Example of an Rspec definition to test an ActiveSupport::Concern

authenticator_spec.rb

require 'spec_helper'

module Api::V1
  describe Concerns::Authenticator, type: :controller do
    controller(ApiController) do
      def fake_current_user
        render json: current_user
      end
    end

    before do
      routes.draw { get 'fake_current_user' => 'api/v1/api#fake_current_user' }
    end

    context "when correctly authenticated" do
      before { signed_get :fake_current_user, nil }

      it { expect(json_response['email']).to_not be_nil }
      it { expect(response.status).to eq 200 }
    end

    context "when not authenticated" do
      before { get :fake_current_user, nil }

      it { expect(response.status).to eq 401 }
    end
  end
end