RSpec Formatter to load SimpleCov

README.markdown

SpecCoverage formatter

This formatter loads SimpleCov a code coverage reporting tool for Ruby 1.9. SimpleCov already does a good job in making it really easy to configure and load itself, but even good efforts can be improved upon.

The only problem is that you'll need to have something like a spec_helper to load it. You might not have this or you might find it ugly having to resort to environment variables to turn it off or on.

With this formatter, SimpleCov will start, and it will load a .coverage file in which you can add ruby code to configure SimpleCov in a non-obtrusive way. Configuration for a typical Rails app will look like this:

SimpleCov.start 'rails'

To run this formatter, place it somewhere in your load path (like inside your spec directory).

This formatter doesn't have any output, so you'll probably want to add another formatter. I prefer the documentation (if the number of specs is limited) or Fuubar formatter (for big spec suites):

rspec spec -f SpecCoverage -f Fuubar

If you are using bundler, then don't forget to add simplecov to your Gemfile:

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

More information on SimpleCov can be found here.

spec_coverage.rb

require 'rspec/core/formatters/base_formatter'
require 'simplecov'

# This formatter does nothing else but run SimpleCov. That means that if you run this formatter on
# its own, you won't get any output. It is advised to add your favorite formatter, like this, to see
# test failures and so on:
#
#   rspec spec -f SpecCoverage -fd
#
class SpecCoverage < ::RSpec::Core::Formatters::BaseFormatter

  def initialize(*)
    super
    add_default_filter
    load_simplecov_config
    start_simplecov
  end

  private

  # This is an RSpec filter, so we can safely assume that specs should be ignored
  def add_default_filter
    SimpleCov.add_filter '/spec/'
  end

  # Load a local .coverage file, to customize it yourself
  #
  # Example contents of this file:
  #
  #   SimpleCov.start do
  #     add_filter '/foo/'
  #   end
  #
  # Rails users might want to add at least something like:
  #
  #   SimpleCov.start 'rails'
  #
  def load_simplecov_config
    load config_file if config_exists?
  end

  def config_exists?
    File.exist?(config_file)
  end

  def config_file
    File.expand_path(".coverage", SimpleCov.root)
  end

  # If you didn't start SimpleCov in your .coverage file, start it now
  def start_simplecov
    SimpleCov.start unless SimpleCov.running
  end

end