try open4 for rubinius [ci skip]

.gemspec

@@ -12,6 +12,7 @@ Gem::Specification.new do |s|
   s.description = "Bahia - where commandline acceptance tests are easy, the people are festive and onde nasceu capoeira. In other words, aruba for any non-cucumber test framework."
   s.required_rubygems_version = ">= 1.3.6"
   s.add_development_dependency 'rspec', '~> 2.7.0'
+  s.add_development_dependency 'open4', '~> 1.3.0'
   s.files = Dir.glob(%w[{lib,spec}/**/*.rb bin/* [A-Z]*.{md,txt,rdoc} ext/**/*.{rb,c} **/deps.rip]) + %w{Rakefile .gemspec}
   s.files += %w{.travis.yml}
   s.extra_rdoc_files = ["README.md", "LICENSE.txt"]

lib/bahia.rb

@@ -30,7 +30,18 @@ def self.run_command(cmd)
     args.unshift Bahia.command
     args.unshift('RUBYLIB' =>
      "#{Bahia.project_directory}/lib:#{ENV['RUBYLIB']}".sub(/:\s*$/, ''))
-    Open3.capture3(*args)
+    exec_command *args
+  end
+
+  def self.exec_command(*args)
+    return Open3.capture3(*args) unless RUBY_DESCRIPTION.include?('rubinius')
+
+    require 'open4'
+    pid, stdin, stdout, stderr = Open4.open4(*args)
+    _, status = Process.wait2(pid)
+    out, err = stdout.read, stderr.read
+    [stdin, stdout, stderr].each(&:close)
+    [out, err, status]
   end
 
   def self.set_project_directory(arr)