Faster RSpec tests with spring

3rd June 2020

TLDR; Click here to jump to the end if you just want fast Ruby tests in VS Code.

I should have done this years ago, if only I knew.

I’ve been doing a lot more JavaScript recently, one of the things I’ve fallen in love with is the speed of testing and the interface provided in VS Code shown below.

VS Code example running Jest

I spend at least as much time if not more in Ruby and am a strong believer in optimising my workflow especially when it clearly pays dividends.

Is It Worth the Time? XKCD comic

After a little bit of research, I find the Ruby Test Explorer extension for VS Code providing a similar UI to the one that VS Code Jest provides.

Screenshot of Ruby Test Explorer

I start using this and within a day become very frustrated about how slow it is and find myself reverting back to the terminal.

Today I found myself doing a bit of housekeeping and increasing test coverage in a few areas of TechTalks, that want for instant feedback returns so I investigate further.

Running RSpec with Spring

How have I never considered this? Also, why is not the default?

Simply adding spring-commands-rspec reduced my single file tests from 4.5s to 0.4s a whopping 91.1% decrease in execution time.


  1. Install VS Code Ruby Test Explorer extension.

  2. Add the spring-commands-rspec gem to your project

     gem 'spring-commands-rspec', group: :development, require: false
  3. Generate the RSpec binstub

     $ bundle exec spring binstub rspec
  4. Configure Ruby Test Explorer to use Spring.

    Ensure the following is set in your workspace or user settings. Mine is within my project at ./.vscode/settings.json.

       "rubyTestExplorer.rspecCommand": "bundle exec spring rspec"


Before After
GIF showing slow result before the change GIF showing fast result after the change