Bill, I assume you've done an ASR before. They aren't hard, but I personally would want to do one or two to be familiar with the phraseology and procedures before I'd do one on a checkride. If you haven't done one yet, then get a CFI or safety pilot (preferably someone who has done one before that can kind of help out if approach throws something weird at you) and give it a try and ask for a circle to land. Although, things like if they will let you circle, and whether or not they clear you to land or make you call up tower could vary from controller to controller or be dependent on how busy the airport is when you are flying in. If you already feel comfortable with the approach itself, then I wouldn't worry too much about the circle. Just listen extra carefully about special instructions like contacting the tower, and of course you hear the magic phrase of cleared to land runway XX.