Ruby on Rails test coverage with simplecov

Question

I want to analyse the test coverage of our code , and therefore, installed the simplecov gem.

Our testing environement has 2 seperate project: REST API test (Java+Rest-Assured) and Web UI testing (Java-Selenium).
As you can see, we dont have unit testing inside the rails app, and we are testing using external projects.

I configured the simplecov gem as descriped in the tutorial and put this, in the rails script:

require 'simplecov'
SimpleCov.start 'rails'
puts "require simplecov"

When loading the app, I see the string I printed.

I ran both automation test projects, saw their printouts in the rails log, but I don't see any coverage of controllers/models, I see only small precentage of initializtion files of some gems and rails.

I searched the net, and tried putting the code phrase in boot.rb or even puma.rb and it returned the same results.

Any ideas?

EDIT

Nothing helped with all the comments, but I figured out something very interesting, in all cases, I only see the name of methods marked as tested, not the content (in controllers).
I tried to put the simplecov start phrase in both bin/rails, puma.rb, config.ru, environment.rb, all not given the desired results of code coverage.

Answer 1

I'm not sure simplecov can measure the whole rails app coverage... But I googled something that you can attach as a rack middleware:

https://github.com/danmayer/coverband

And it's output is compatible with simplecov. So it looks like it could be useful in your case.

As you mentioned in your question you're using puma. I suspect that, since it's multi-threaded, it spawns a few rails apps and their simplecov output overwrites each other's results. I'd try with the single threaded server like webrick - but this may make your tests slower (depending on how the tests are fired up really) or try the coverband gem.

Also - even if the server is single threaded - I'm not sure if each request would not overwrite simplecov's output.