Sean “Diddy” Combs’s federal sex-trafficking trial will end its first week of testimony Friday with more cross-examination of the prosecution’s star witness, Casandra “Cassie” Ventura. Combs, 55, has pleaded not guilty to charges of sex trafficking, racketeering, conspiracy and transportation to engage in prostitution, and he faces 15 years to life in prison if convicted on all counts by the jury.