/usr/lib/ruby/vendor_ruby/active_support/testing/autorun.rb is in ruby-activesupport 2:4.2.10-0ubuntu4.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 | gem 'minitest'
require 'minitest'
Minitest.autorun
|