Speeding up RSpec with bundler standalone and springified binstubs

Testing Rails with RSpec is slow, or at least it feels slow to me in all the projects I am working on. Any speed gain helps my productivity when it reduces the time I'm waiting between writing code and running tests.

There are quite a few posts out there that tackle this problem. But most are pretty old, and none really worked for me, so I'm not going to link to them.

The book I'm reading inspired me to look into the bundler --standalone command. Not that I really understand what's happening there, but at least I got a little bit of a speed bump out of it.

Here's what I did, and how I'm running my tests now.


First I made sure my Rails app is installed with Spring enabled. Luckily, this is the default. In order to later run RSpec from spring, I added the spring-commands-rspec gem to my Gemfile.

gem 'spring-commands-rspec'


Next, I used bundler's standalone command,

$ bundle install --standalone --path .bundle

and then "springified" the installed binstubs.

$ bundle exec spring binstub --all


I encountered a problem with SQLite 1.4.0. I didn't investigate it further, but pinned the gem to version 1.3 instead.

group :development, :test do
  gem "sqlite3", "~> 1.3.6"

Afterwards I repeated the install command.

$ bundle install --standalone --path .bundle

Anytime you want to use bundle install, you now have to use bundle install --standalone instead. I created the bash alias bis for that.


I recently started using the vim-test plugin. That plugin has a neat option that makes it use the springified binstubs.

" .vimrc

let test#ruby#use_spring_binstub = 1

Now, when I'm editing app/models/transformer_spec.rb and I hit the return key in normal mode, vim-test executes

$ ./bin/spring rspec spec/models/transformer_spec.rb

Because of spring, everything's faster and I have actually seen tests being executed in less than a second. Still not super fast but better than before.