start_watchdog

# File lib/test/unit.rb, line 511
      def start_watchdog
        Thread.new do
          while stat = Process.wait2
            break if @interrupt # Break when interrupt
            pid, stat = stat
            w = (@workers + @dead_workers).find{|x| pid == x.pid }
            next unless w
            w = w.dup
            if w.status != :quit && !w.quit_called?
              # Worker down
              w.died(nil, !stat.signaled? && stat.exitstatus)
            end
          end
        end
      end