Introduce capybara-screenshot to make debugging easier

Gemfile

@@ -149,6 +149,7 @@ group :development do
   group :test do
     gem 'coveralls', '~> 0.7.4', require: false
     gem 'capybara', '~> 2.13.0'
+    gem 'capybara-screenshot'
     gem 'capybara-select2', require: false
     gem 'delorean'
     gem 'poltergeist'

Gemfile.lock

@@ -170,6 +170,9 @@ GEM
       rack (>= 1.0.0)
       rack-test (>= 0.5.4)
       xpath (~> 2.0)
+    capybara-screenshot (1.0.17)
+      capybara (>= 1.0, < 3)
+      launchy
     capybara-select2 (1.0.1)
       capybara
       rspec
@@ -625,6 +628,7 @@ DEPENDENCIES
   capistrano-bundler (~> 1.1.4)
   capistrano-rails (~> 1.1)
   capybara (~> 2.13.0)
+  capybara-screenshot
   capybara-select2
   coffee-rails (~> 4.2)
   coveralls (~> 0.7.4)

spec/capybara_helper.rb

@@ -1,6 +1,7 @@
 require 'rails_helper'
 require 'capybara/rails'
 require 'capybara/poltergeist'
+require 'capybara-screenshot/rspec'
 require 'capybara-select2'
 
 CAPYBARA_TIMEOUT = ENV['CI'] == 'true' ? 60 : 5
@@ -12,6 +13,8 @@ end
 Capybara.javascript_driver = :poltergeist
 Capybara.default_max_wait_time = CAPYBARA_TIMEOUT
 
+Capybara::Screenshot.prune_strategy = { keep: 3 }
+
 RSpec.configure do |config|
   config.include Warden::Test::Helpers
   config.include AlertConfirmer, type: :feature