Why the hell Microsoft thought it was a good idea to remove this I have no idea. If they want good reliable code on their platforms you would have thought this would be good to leave in to encourage developers to create unit tests!
Anyway, rant over, this blog explains all the options. The last one being the first one to try!
http://serena-yeoh.blogspot.com.es/2013/02/visual-studio-2012-create-unit-test.html