I just installed the SimpleCov gem to generate code coverage reports on my Rails

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Asked: June 10, 20262026-06-10T13:09:12+00:00 2026-06-10T13:09:12+00:00

I just installed the SimpleCov gem to generate code coverage reports on my Rails

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I just installed the SimpleCov gem to generate code coverage reports on my Rails 3.2.6 app, and it works great with RSpec, just not with Spork. I am able to get the desired correct report by running rspec --no-drb spec/, but I’d like to also get them with Spork running using just rspec spec/.

Given that there have been people who have had success with this, it seems likely I have errors in my setup. I have read through the setup instructions as well as the GitHub issue that purports to have a fix for Spork users, but still no luck. I’m wondering if there is anyone who can provide a full example of their working spec/spec_helper.rb file that I could use for reference, as extensive Googling has only turned up snippets. On the advice of other sites, I’ve tried changing the config.cache_classes in config/environments/test.rb from the default of true to false to !(ENV['DRB'] == 'true'), with no luck.

For reference, this is how I’m setup:

Gemfile

group :development, :test do
  # ...
  gem 'rspec-rails', '2.10.1'
end

group :test do
  # ...
  gem 'spork', '0.9.0'
  gem 'simplecov', '0.6.4', require: false
end

.spec

--colour
--drb

spec/spec_helper.rb (changed as per the GitHub issue)

require 'simplecov'
SimpleCov.start 'rails'

require 'rubygems'
require 'spork'

Spork.prefork do
  unless ENV['DRB']
    require 'simplecov'
    SimpleCov.start 'rails'
  end

  ENV["RAILS_ENV"] ||= 'test'
  require File.expand_path("../../config/environment", __FILE__)
  require 'rspec/rails'
  require 'rspec/autorun'

  Dir[Rails.root.join("spec/support/**/*.rb")].each {|f| require f}

  RSpec.configure do |config|
    config.mock_with :rspec
    config.fixture_path = "#{::Rails.root}/spec/fixtures"
    config.use_transactional_fixtures = true
    config.infer_base_class_for_anonymous_controllers = false
  end
end

Spork.each_run do
  if ENV['DRB']
    require 'simplecov'
    SimpleCov.start 'rails'
  end
end

I’ve tried commenting out/changing the top two SimpleCov statements of this file and the Simplecov statements inside the Spork blocks, but can’t seem to find a combination that works.

What am I missing? Are there any other files I need to change?

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1 Answer

Editorial Team · Answer 1 · 2026-06-10T13:09:13+00:00

I managed to get a working spec/spec_helper.rb configuration that executes SimpleCov correctly simply using the $ rspec spec/ command thanks to a comment on the Github issue that sent me to this blog entry, and its example spec/spec_helper.rb. All reasons why this works are contained in the (very detailed!) blog entry. Replace SampleApp with the name of your application.

spec/spec_helper.rb

require 'rubygems'
require 'spork'

Spork.prefork do
  unless ENV['DRB']
    require 'simplecov'
    SimpleCov.start 'rails'
  end

  require 'rails/application'
  require Rails.root.join("config/application")

  ENV["RAILS_ENV"] ||= 'test'
  require 'rspec/rails'
  require 'rspec/autorun'

  RSpec.configure do |config|
    config.mock_with :rspec
    config.fixture_path = "#{::Rails.root}/spec/fixtures"
    config.use_transactional_fixtures = false

    config.before :each do
      if Capybara.current_driver == :rack_test
        DatabaseCleaner.strategy = :transaction
      else
        DatabaseCleaner.strategy = :truncation
      end
      DatabaseCleaner.start
    end

    config.after do
      DatabaseCleaner.clean
    end

    config.infer_base_class_for_anonymous_controllers = false
  end
end

Spork.each_run do
  if ENV['DRB']
    require 'simplecov'
    SimpleCov.start 'rails'
    SampleApp::Application.initialize!
    class SampleApp::Application
      def initialize!; end
    end
  end

  Dir[Rails.root.join("spec/support/**/*.rb")].each {|f| require f}
end

Edit

If you use Travis-CI, don’t use this code as-is because you’ll likely get a undefined method 'root' for Rails:Module (NoMethodError) error. If you know how to fix this, please share.

Edit 2

I got Travis CI to work by essentially putting everything in the Spork.each_run block, which seems to have slowed down the tests significantly. There must be a better way to do this, or it just doesn’t seem worth it for the sake of not having to run $ rspec --no-drb spec/ once to get the SimpleCov report…

spec/spec_helper.rb

require 'rubygems'
require 'spork'

Spork.prefork do
  unless ENV['DRB']
    require 'simplecov'
    SimpleCov.start 'rails'
  end

  require 'rails/application'
  ENV["RAILS_ENV"] ||= 'test'
end

Spork.each_run do
  if ENV['DRB']
    require 'simplecov'
    SimpleCov.start 'rails'
    require Rails.root.join("config/application")
    SampleApp::Application.initialize!
    class SampleApp::Application
      def initialize!; end
    end
  end

  unless ENV['DRB']
    require File.expand_path("../../config/environment", __FILE__)
  end

  require 'rspec/rails'
  require 'rspec/autorun'

  Dir[Rails.root.join("spec/support/**/*.rb")].each {|f| require f}

  RSpec.configure do |config|
    config.mock_with :rspec

    config.fixture_path = "#{::Rails.root}/spec/fixtures"
    config.use_transactional_fixtures = false
    config.before :each do
      if Capybara.current_driver == :rack_test
        DatabaseCleaner.strategy = :transaction
      else
        DatabaseCleaner.strategy = :truncation
      end
      DatabaseCleaner.start
    end

    config.after do
      DatabaseCleaner.clean
    end
    config.infer_base_class_for_anonymous_controllers = false
  end
end

Edit 3

After using this config for a few days, it doesn’t seem to have slowed down things as much as I previously thought, so I’ll consider this the accepted answer unless a more elegant one is posted.

Edit 4

After using this config for a few months, I’ve come to realize that it is slower than I thought. Part of that is the realisation that it seems that Spork can slow down test suites, and is best for fast iterative focused testing vs always running entire test suites with it. The following SO questions and blog posts got me to the spec_helper.rb file below, which can run SimpleCov with or without Spork, runs faster than before, and works with Capybara 2.0.

spec/spec_helper.rb

require 'rubygems'
require 'spork'
require 'simplecov'
#uncomment the following line to use spork with the debugger
#require 'spork/ext/ruby-debug'

Spork.prefork do
  ENV["RAILS_ENV"] ||= 'test'
  unless ENV['DRB']
    SimpleCov.start 'rails'
    require File.expand_path("../../config/environment", __FILE__)
  end

  require 'rspec/rails'
  require 'rspec/autorun'
  require 'capybara/rails'
  require 'capybara/rspec'

  # files to preload based on results of Kernel override code below
  # ie they took more than 100 ms to load
  require "sprockets"
  require "sprockets/eco_template"
  require "sprockets/base"
  require "active_record/connection_adapters/postgresql_adapter"
  require "tzinfo"
  require "tilt"
  require "journey"
  require "journey/router"
  require "haml/template"

  RSpec.configure do |config|
    config.mock_with :rspec

    # If you're not using ActiveRecord, or you'd prefer not to run each of your
    # examples within a transaction, remove the following line or assign false
    # instead of true.
    config.use_transactional_fixtures = false

    # If true, the base class of anonymous controllers will be inferred
    # automatically. This will be the default behavior in future versions of
    # rspec-rails.
    config.infer_base_class_for_anonymous_controllers = false

    config.include FactoryGirl::Syntax::Methods

    config.before :suite do
      # PerfTools::CpuProfiler.start("/tmp/rspec_profile")
      DatabaseCleaner.strategy = :transaction
      DatabaseCleaner.clean_with(:truncation)
    end

    # Request specs cannot use a transaction because Capybara runs in a
    # separate thread with a different database connection.
    config.before type: :request do
      DatabaseCleaner.strategy = :truncation
    end

    # Reset so other non-request specs don't have to deal with slow truncation.
    config.after type: :request  do
      DatabaseCleaner.strategy = :transaction
    end

    RESERVED_IVARS = %w(@loaded_fixtures)
    last_gc_run = Time.now

    config.before(:each) do
      GC.disable
    end

    config.before do
      DatabaseCleaner.start
    end

    config.after do
      DatabaseCleaner.clean
    end

    # Release instance variables and trigger garbage collection
    # manually every second to make tests faster
    # http://blog.carbonfive.com/2011/02/02/crank-your-specs/
    config.after(:each) do
      (instance_variables - RESERVED_IVARS).each do |ivar|
        instance_variable_set(ivar, nil)
      end
      if Time.now - last_gc_run > 1.0
        GC.enable
        GC.start
        last_gc_run = Time.now
      end
    end

    config.after :suite do
      # PerfTools::CpuProfiler.stop

      # REPL to query ObjectSpace
      # http://blog.carbonfive.com/2011/02/02/crank-your-specs/
      # while true
      #   '> '.display
      #   begin
      #     puts eval($stdin.gets)
      #   rescue Exception => e
      #     puts e.message
      #   end
      # end
    end
  end

  # Find files to put into preload
  # http://www.opinionatedprogrammer.com/2011/02/profiling-spork-for-faster-start-up-time/
  # module Kernel
  #   def require_with_trace(*args)
  #     start = Time.now.to_f
  #     @indent ||= 0
  #     @indent += 2
  #     require_without_trace(*args)
  #     @indent -= 2
  #     Kernel::puts "#{' '*@indent}#{((Time.now.to_f - start)*1000).to_i} #{args[0]}"
  #   end
  #   alias_method_chain :require, :trace
  # end
end

Spork.each_run do
  # This code will be run each time you run your specs.
  if ENV['DRB']
    SimpleCov.start 'rails'
    SampleApp::Application.initialize!
    class SampleApp::Application
      def initialize!; end
    end
  end

  # Requires supporting ruby files with custom matchers and macros, etc,
  # in spec/support/ and its subdirectories.
  Dir[Rails.root.join("spec/support/**/*.rb")].each {|f| require f}
  FactoryGirl.reload
  I18n.backend.reload!
end

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