If it's so easy create things for your portfolio and history of work, why can't you just perform some of the tasks required for the job during the interview? You hire a chef by watching them cook. They either cook good tasting food (code) in a reasonable amount of time and act like they know their way around a kitchen (IDE) or they don't. They may have to ask where everything is and substitute ingredients, but they should be able to do that without a total meltdown.