Configure coveralls.

.coveralls.yml

@@ -0,0 +1 @@
+repo_token: 6TBOCfVJmaf2hdCQLUaO6aFptRqL2sfcK

.gitignore

@@ -7,3 +7,4 @@ tmp
 Gemfile.lock
 /.rbx/
 /.bundle
+coverage

Gemfile

@@ -8,3 +8,8 @@ group :debug do
   gem "byebug", platform: :mri
   gem 'awesome_print',    github: 'akshaymohite/awesome_print'
 end
+
+group :development, :test do
+  gem 'simplecov',  platforms: :mri
+  gem 'coveralls',  '~> 0.8', platforms: :mri
+end

README.md

@@ -4,6 +4,7 @@ This is a Ruby implementation of a universal [S-expression][] parser.
 
 [![Gem Version](https://badge.fury.io/rb/sxp.png)](https:/badge.fury.io/rb/sxp)
 [![Build Status](https://github.com/dryruby/sxp.rb/workflows/CI/badge.svg?branch=develop)](https://github.com/dryruby/sxp.rb/actions?query=workflow%3ACI)
+[![Coverage Status](https://coveralls.io/repos/dryruby/sxp.rb/badge.svg)](https://coveralls.io/r/dryruby/sxp.rb)
 
 ## Features
 

spec/spec_helper.rb

@@ -3,6 +3,21 @@
 
 require "bundler/setup"
 require 'rspec'
+
+begin
+  require 'simplecov'
+  require 'coveralls'
+  SimpleCov.formatter = SimpleCov::Formatter::MultiFormatter.new([
+    SimpleCov::Formatter::HTMLFormatter,
+    Coveralls::SimpleCov::Formatter
+  ])
+  SimpleCov.start do
+    add_filter "/spec/"
+  end
+rescue LoadError => e
+  STDERR.puts "Coverage Skipped: #{e.message}"
+end
+
 require 'sxp'
 
 include SXP