I use HTTP status code symbols in code in a controller such as:
render json: { auth_token: user.authentication_t
With rspec-rails (as of rspec 3) it's possible to use
expect(response).to have_http_status(:created)
Update 2018-06-11:
As of Rails 6, some of the matchers will be replaced (e. g. success by successful).
success
successful