---
title: Running Specs from Vim, Sent to tmux via Tslime
teaser:
tags: web,tmux,vim,ruby,testing
author: Joël Quenneville
published_on: 2013-08-08
---

When I first started working at thoughtbot, I was impressed to see some of my
colleagues sending the current spec in vim to a tmux pane with the press of a
key. This makes for an very fast testing/feedback loop and streamlines the TDD
process.

## Determining which spec(s) to run

We don't always want to run the full test suite. Often, we just want to run a
single spec or even a single example. We recently released
[vim-rspec](https://thoughtbot.com/blog/running-specs-from-vim),
a vim plugin that allows us to run the desired set of specs with the press of a
key.

## Sending the spec command

`vim-rspec` only does half the job however. We need a second component to send
the commands from vim to the desired tmux pane.
[tslime.vim](https://github.com/jgdavey/tslime.vim) is a plugin that
does exactly that by providing a `Send_to_Tmux()` function.

## Tying it all together

First install `vim-rspec` and `tslime.vim` using
[Vundle](https://github.com/gmarik/vundle):

    Bundle 'thoughtbot/vim-rspec'
    Bundle 'jgdavey/tslime.vim'

Add the following to your `.vimrc`:

    let g:rspec_command = 'call Send_to_Tmux("rspec {spec}\n")'

This tells `vim-rspec` to use `Send_to_Tmux` to run the selected specs.

Finally, all this wouldn't be of much use if we couldn't run it at the press of
a key. Add these keybindings to your `.vimrc` (this step is unnecessary if
you're using [thoughtbot/dotfiles](https://github.com/thoughtbot/dotfiles)):

    " vim-rspec mappings
    map <Leader>t :call RunCurrentSpecFile()<CR>
    map <Leader>s :call RunNearestSpec()<CR>
    map <Leader>l :call RunLastSpec()<CR>
    map <Leader>a :call RunAllSpecs()<CR>

Thats all you have to do! The first time you run a spec this way, you will be
asked to input the names of your tmux session, window and pane (protip, you can
tab-complete these). Every subsequent time, your tests will just magically run
in the desired pane without you ever needing to leave vim.

## Bonus

You can completely customize the command that gets sent to your tmux pane. For
example, to run the specs using [Spring](https://github.com/jonleighton/spring)
you would use

    let g:rspec_command = 'call Send_to_Tmux("spring rspec {spec}\n")'