Coverfield

Warning: This is a Beta Release!

One day I found a class in my ruby app with > 95% coverage in SimpleCov but without any dedicated spec. SimpleCov is an awesome tool if you want to get an idea of your test coverage, but it has a flaw: It doesn't look whether there's a spec for a class/module/method or not, it just reports if a line of code was executed while the spec suite run through. In my case a class which was used relative often so gathered nearly 100% coverage, but I've never wrote any line of testing code specific vor that class.

To get an overview which classes, modules and methods my test suite covers (and more important: which not), I've wrote a small script, which scans all production code, finds the classes and methods and checks if there are dedicated tests for that methods within the specs. It compiles a report which clearly tells me, what specs are missing.

This script is not a substitution for SimpleCov! SimpleCov is a wonderful piece of software and it's coverage report is very important. Think of Coverfield as a additional tool for examining the quality of your test suite under another aspect and from a different view.

Together SimpleCov and Coverfield can tell you accurate how good or bad your coverage really is: Coverfield tells you which methods, classes and files are covered by specs and which not. SimpleCov then tells you how well the body of those methods is tested and if there are edge cases which are not touched by the test suite.

Click here for a screenshot of the coverfield generated report.

Future

This gem is still in beta phase and there's plenty to do (specs for example).

And I wrote Christoph Olszowka to ask him if there is a chance that this will be included to SimpleCov in some way. I would really appreciate that!

Thanks

Big thanks and Kudos to the folks of RuboCop! Coverfield is based on the AST Ruby Parser, which is part of the RuboCop gem. Without that awesome peace of software, coverfield would have been much more code and much more complicated. Thank you very much, nice work!

Also thanks to Christoph Olszowka for his SimpleCov gem, I really hope there will be some kind of integration in the future.

Usage

Install via gem install coverfield.

Then just call coverfield -u lib/ app/ in your apps root dir.

For more info take a look at the usage information of coverfield -h.

Considerations

Coverfield requires you to have a specific architecture of your RSpec Suite.

1. Within the spec directory all specs are placed in the same path as the file which is tested by the spec. For example the spec for the file /lib/some/nice_class.rb have to be placed in /spec/lib/some/nice_class_spec.rb or /spec/some/nice_class_spec.rb. And the spec for the file /app/models/post.rb goes to /spec/app/models/post.rb or /spec/models/post.rb Why?
2. The first describe call have to be built like that: describe Some::NiceClass do assuming, that /lib/some/nice_code.rb defines the class Some::NiceClass. Why?
3. All inner describe calls for the methods have to be built like that: describe '#method_name' do. The # is optional and may also be a .. Why?
4. All dependencies of your app have to be installed (bundle install).