Beta is currently closed. Whenever it opens it is to test {x} specific heroes; other heroes are not tested nescessarily (unless they are owned already by a beta tester).
There are other threads which explain how Beta Testing works etc… I’ve written some long posts on the subject previously also. {example here: [SOLVED] Ninja Troop in Live Game...? - #35 by Guvnor}
There is a Link in the OP to a #beta-beat thread specifically for the S4 heroes.