Assert that a set of specs actually give 100% coverage for the files they're supposed to test.

check_coverage.rb

#!/usr/bin/env ruby

COVERED = %w{
  app/models/ ...
}

failures = COVERED.select do |app_file|
  spec_file = app_file.gsub('app', 'spec').gsub('.rb', '_spec.rb')
  cmd = "sh -c 'SIMPLECOV_FOR=#{app_file} rspec #{spec_file}'"
  puts "Running #{cmd}"
  system cmd
  $?.to_i != 0
end

if failures.length > 0
  puts "The following files do not have 100% coverage or had test failures:"
  puts failures.join("\n")
  exit 1
end

spec_helper.rb

require 'simplecov'    

# Note: will NOT work with Spork in an each_run block as there is no way
# to send the environment variable to it :(

SimpleCov.start 'rails' do
  if ENV['SIMPLECOV_FOR']
    add_filter do |source_file|
      source_file.filename != Rails.root.join(ENV['SIMPLECOV_FOR']).to_s
    end
    minimum_coverage 100
    coverage_dir 'coverage/' + ENV['SIMPLECOV_FOR']
  end
end

# .. everything else ..