need an ITV test centre in roses

There isn't one in Roses. The Spanish system isn't like in countries where vehicle testing is carried out in thousands of garages or test centres. There are relatively few locations and the nearest to Roses is in the industrial area at Vilamalla, off the N11 Figueres by-pass. (You also need an appointment from citaprevia.cat.) Following lock-down, I believe that there's a significant wait for an appointment. (Search Google for PrevenControl ITV Vilamalla to get its location.)

You may find that a local garage will arrange it all for you for a fee, but I don't know of one that does this, but there's no harm in asking.