Code coverage with SimpleCov in rails

on rails and testing

I wanted my rails application to communicate with an API still under heavy development by my collegue. I wasn't writing test cases because we were still discovering how to implement this API. Not a best practice ;)

This also meant I lost sight what I covered in my test suite and what not. So I investigated a code coverage tool.

I found SimpleCov and it's indeed simple. It works for several test suites in rails and it's quite easy to setup. In my case it was Rspec.

Add SimpleCov to your Gemfile and bundle install:

 gem 'simplecov', :require => false, :group => :test

I'm using Rspec so at the top of spec_helper.rb (the very top):

 require 'simplecov'
 SimpleCov.start

 # Previous content of test helper now starts here

Don' forget to:

  bundle

Now we can just run rspec spec and you will see something like:

 Coverage report generated for RSpec to /Users/me/Code/some_app/coverage. 1340 / 1570 LOC (85.35%) covered.

in this folder there is a index.htmlfile which can be opened in your browser.

I'm quite happy I still have 85% of my code covered with tests. It wasn't as bad as I thougt.