It seems you could do this already with :AV. I’ll leave this post here for posterity’s sake.
Using vim for Rails development I often found myself entering
:Rcont :vsp :A
to see my controller spec on the left, with my controller on the right. now with this in my .vimrc:
nmap vspa :vsp<cr>:A<cr> nmap RC :only<cr> :Rcontroller<cr> :vsp<cr> :A<cr> nmap RM :only<cr> :Rmodel<cr> :vsp<cr> :A<cr>
I can do it all at once with just the following in normal mode Rspec and Controller:
Rspec and Model:
vertically split, and then open the associated file: