Very simple - sends a command from vim to run your rspec in your existing iTerm window. No more, no less. I looked around and found many variations on this theme, but none that did exactly what I want.
This one does not use bundle exec because it assumes you have a smart shell that understands bundler (zsh with bundler plugin). Also it is more universal without assuming bundle exec so that you can run truly fast specs without bundler.
Stolen from lparry/vim-iterm-rspec and modified to support running specs with spring for running quick Rails specs, or just naked rspec for fast specs.
This plugin is included in the YADR dotfile project
RunItermSpec
RunItermSpecLine
RunItermSpringSpec
RunItermSpringSpecLine
map <D-r> :RunItermSpec<cr>
map <D-l> :RunItermSpecLine<cr>
map <D-R> :RunItermSpringSpec<cr>
map <D-L> :RunItermSpringSpecLine<cr>