Yep - I'm flying out Sunday 25th and will watch the first two days before returning on the Wednesday. Not a good time to go again this year, to be honest, as it once again clashes with the World Mobile Conference or something - hotel prices are through the roof across the city. So we're staying in the suburbs, out in Sant Adria de Besos. Hiring a car from the airport and will drive to the track each day. I think this is our sixth year of testing now - still preferred Jerez but you can get to more of the track in Barcelona.
If you don't have a car then just get the train to Montmelo and walk - about 20 mins or so from there. If there's a group of you then just get a cab - 40 / 50 Euro if you book in advance from the centre.
If you don't want to stay in Barcelona then there are a few reasonable towns on the outskirts that still have a few good bars and restaurants, but it may be more difficult without a car. We stayed in Sabadelle last year, but it seems that it is not immune from the hotel price gouging this year.