The goal of this component is to find what RSpec examples "cover" one or more lines of code of a Ruby project.

This is useful for example when you override methods of a parent product and you want to check what/how the specs treat the original lines.

Blog post introduction: https://nebulab.it/blog/reverse-coverage/

Add gem 'reverse_coverage' to your application's Gemfile and execute bundle.

Put the following code under you specs configuration:

require 'reverse_coverage'

RSpec.configure do |config|
  config.before(:suite) do
    ReverseCoverage::Main.start
  end

  config.around do |e|
    e.run
    ReverseCoverage::Main.add(e)
  end

  config.after(:suite) do
    ReverseCoverage::Main.save_results
    coverage_matrix = ReverseCoverage::Main.coverage_matrix
    ReverseCoverage::Formatters::HTML::Formatter.new.format(coverage_matrix)
  end
end

Run your specs, inspect the 'tmp/reverse_coverage.yml' file or open 'tmp/index.html' file.

To configure the base URL used to open a specific spec edit the generated 'tmp/settings.js' file. Without changes, the default behavior is to open files locally.

• file_filter: allows to set a lambda to filter what files belongs to the project. Example (to add before ReverseCoverage::Main.start line): ReverseCoverage::Main.config[:file_filter] = ->(file_path) { file_path.include? 'faked_project' }

Execute bundle exec rspec on the component root path, specs are based on an internal fake project.

Here it is a screenshot of the generated HTML interface:

Bug reports and pull requests are welcome on GitHub at https://github.com/nebulab/reverse_coverage. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the Contributor Covenant code of conduct.

ReverseCoverage is copyright © 2019 Nebulab. It is free software, and may be redistributed under the terms specified in the license.

ReverseCoverage is funded and maintained by the Nebulab team.

We firmly believe in the power of open-source. Contact us if you like our work and you need help with your project design or development.