A metrics:rake task for rails (WIP)

mutant.rake

# encoding: utf-8

if defined?(::Devtools)

  # Load all rake tasks
  Rake.application.load_imports

  # Remove metrics:mutant from devtools
  task('metrics:mutant').clear

  namespace :metrics do
    allowed_versions = %w(mri-1.9.3 mri-2.0.0 rbx-1.9.3)

    enabled = begin
      require 'mutant'
      defined?(Mutant)
    rescue LoadError
      false
    end

    config    = Devtools.project.mutant
    enabled &&= config.enabled? && !ENV['DEVTOOLS_SELF']

    if enabled && allowed_versions.include?(Devtools.rvm)
      desc 'Run mutant'
      task mutant: :coverage do

        # Eager load application and dependencies
        require File.expand_path('../../../config/environment', __FILE__)

        # All classes in the system
        original = ObjectSpace.each_object(Class).to_a

        Rails.application.eager_load!

        classes = (ObjectSpace.each_object(Class).to_a - original).map(&:name)

        # Remove classes in namespaces that should not be mutation covered
        classes -= classes.grep(/\A(?:ActionView|Devise|Spree)::/)

        status = Mutant::CLI.run([*classes, config.strategy])

        if status.nonzero?
          Devtools.notify 'Mutant task is not successful'
        end
      end
    else
      desc 'Run Mutant'
      task mutant: :coverage do
        $stderr.puts 'Mutant is disabled'
      end
    end
  end
end

@dkubb A mutant rails integration would basically ad a "--rails" flag calling the following loc?

# path maybe needs a fix
require File.expand_path('../../../config/environment', __FILE__)
Rails.application.eager_load!

The rest is scenario specific?

undefined method `init_project' for Devtools:Module

@dkubb, do you still make use of this script? I've modified it somewhat: https://gist.github.com/mockdeep/7014387

But I'm still getting some issues. Stack trace posted here: mbj/mutant#21 (comment)

I'd love to get a better sense for how you're running mutant in rails.

@mockdeep I've updated the rake task with the latest version of my mutant task.

Excellent. This is going to be really helpful. Thanks!

Hmm, running into some issues with this. The problem is that I have testing gems like webmock and vcr that don't get loaded with the script. It's loading classes in dev mode. But then when I try to run in test mode everything is already loaded, so the difference in classes is empty. Not sure of a good way around it.