If I am bottling I go ahead and put it in a bottle anyway - that's the one I pop open in a few weeks to check for carbonation.
When kegging I use a growler or lately I have been using those carb caps to "hurry up and try some". The work real well. Sometimes I use them when I don;t know if I should carbonate something like an apfelwein or cider ... let's me carbonate a little bit.
Bad decisions make good stories.