Movie rentals are coming to Facebook. Warner Bros. says it is testing a service that will offer select movies for purchase or rental through the world’s largest online social network. Starting Tuesday, Facebook users

who visit the official page of “Batman: The Dark Knight” can click a “watch” icon and pay 30 Facebook credits, or $3, to watch the movie. The movie is streamed through a Facebook application. Renters have access to a movie for 48 hours and can replay it as many times as they like. Warner Bros. said it will add other movies in coming months but did not say which ones. The page had nearly 4 million “likes” as of Tuesday afternoon. Another page, called simply “Dark Knight,” had about 2 million – but this is not the official Warner Bros. page and the movie isn’t available through it. Warner Bros. didn’t say how much it will cost to buy movies.