RSpec 3.1 and Rails 4 HTTP Digest Auth testing

api_clients_controller_spec.rb

# spec/controllers/api_clients_controller_spec.rb
RSpec.describe APIClientsController, type: :controller do
  let(:api_client) { mock_model(APIClient) }

  context "when HTTP Digest auth credentials are invalid" do
    before do
      authenticate_with_http_digest("invalid_login", "invalid_password") do
        get :index
      end
    end

    it { should respond_with(:unauthorized) }
  end

  context "when HTTP Digest auth credentials are missing" do
    before do
      get :index
    end

    it { should respond_with(:unauthorized) }
  end

  describe "GET #index" do
    before do
      expect(APIClient).to receive(:ordered_by_name).and_return([:api_client1, :api_client2])
      authenticate_with_http_digest("valid_username", "valid_password") do
        get :index
      end
    end

    it "loads @api_clients to be shown in the template" do
      expect(assigns[:api_clients]).to eq([:api_client1, :api_client2])
    end

    it { should respond_with(:success) }
    it { should render_template(:index) }
  end
end

digest_auth_helpers.rb

# spec/support/digest_auth_helpers.rb
module SpecHelpers
  module DigestAuthHelpers

    def authenticate_with_http_digest(user, password, &request_trigger)
      request.env['HTTP_AUTHORIZATION'] = encode_credentials(user, password, &request_trigger)
      request_trigger.call
    end

    # Shamelessly stolen from the Rails 4 test framework.
    # See https://github.com/rails/rails/blob/a3b1105ada3da64acfa3843b164b14b734456a50/actionpack/test/controller/http_digest_authentication_test.rb
    def encode_credentials(user, password, &request_trigger)
      # Perform unauthenticated request to retrieve digest parameters to use on subsequent request
      request_trigger.call
      expect(response).to have_http_status(:unauthorized)

      credentials = decode_credentials(response.headers['WWW-Authenticate'])
      credentials.merge!({ username: user, nc: "00000001", cnonce: "0a4f113b", password_is_ha1: false })
      path_info = request.env['PATH_INFO'].to_s
      credentials.merge!(uri: path_info)
      request.env["ORIGINAL_FULLPATH"] = path_info
      ActionController::HttpAuthentication::Digest.encode_credentials(request.method, credentials, password, credentials[:password_is_ha1])
    end

    # Also shamelessly stolen from the Rails 4 test framework.
    # See https://github.com/rails/rails/blob/a3b1105ada3da64acfa3843b164b14b734456a50/actionpack/test/controller/http_digest_authentication_test.rb
    def decode_credentials(header)
      ActionController::HttpAuthentication::Digest.decode_credentials(header)
    end

  end
end

rails_helper.rb

# spec/rails_helper.rb

RSpec.configure do |config|

  # ...
  config.include SpecHelpers::DigestAuthHelpers, type: :controller
end