Add SimpleCov

pry.gemspec

@@ -26,6 +26,7 @@ Gem::Specification.new do |s|
   s.add_development_dependency 'rake',  '~> 0.9'
   s.add_development_dependency 'guard', '~> 1.3.2'
   s.add_development_dependency 'mocha', '~> 0.13.1'
+  s.add_development_dependency 'simplecov'
   # TODO: make this a plain dependency:
   s.add_development_dependency 'bond',  '~> 0.4.2'
 end

spec/helper.rb

@@ -1,3 +1,8 @@
+if ENV["COVERAGE"]
+  require "simplecov"
+  SimpleCov.start
+end
+
 unless Object.const_defined? 'Pry'
   $:.unshift File.expand_path '../../lib', __FILE__
   require 'pry'