「Allow this application to be used to Sign in with Twitter」[これにチェックを入れていないと /oauth/authenticate の代わりに /oauth/authorize に飛ばされるため、ログインの度に毎回アプリケーションにアクセスを許可するかどうか聞かれる」
Stubs provide canned answers to calls made during the test, usually not responding at all to anything outside what's programmed in for the test. / Mocks are what we are talking about here: objects pre-programmed with expectations which form a specification of the calls they are expected to receive.