avoid using pry on Travis

Author: e2

test/test_helper.rb

@@ -4,6 +4,6 @@
 require 'guard/compat/test/helper'
 require 'guard/process'
 
-require 'pry'
+require 'pry' unless ENV['CI'] == 'true'
 
 TEST_ROOT = File.expand_path(File.dirname(__FILE__))