I was one week in Testaccio and Nadias flat was the perfect place to explore Rome in detail. The appartement is absolutely recommendable. It is close to the Pyramide metro station and in 300 m distance all relevant bus lines start from there. The flat has everything that you need for an comfortable stay. Next to the flat are many restaurants and cafes; Trastevere is also just around the corner. You can go by bike to see Via Appia Antica in 30 minutes. All in all a great choice for a 1-2 weeks stay in Rome.