Tesla is set to begin a test of its long-promised robotaxi service on schedule in Austin, Texas, by the end of June, Chief Executive Elon Musk said on Tuesday, even as the company faces questions from a U.S. regulator on safety. The electric vehicle maker will roll out about 10 self-driving cars in some parts of the city, Musk said in an interview with CNBC, adding that robotaxi deployment would scale up to about a thousand within a few months. "We are actually going to deploy not to the entire