autorun

# File lib/minitest/unit.rb, line 652
    def self.autorun
      at_exit {
        next if $! # don't run if there was an exception

        # the order here is important. The at_exit handler must be
        # installed before anyone else gets a chance to install their
        # own, that way we can be assured that our exit will be last
        # to run (at_exit stacks).
        exit_code = nil

        at_exit { exit false if exit_code && exit_code != 0 }

        exit_code = MiniTest::Unit.new.run ARGV
      } unless @@installed_at_exit
      @@installed_at_exit = true
    end