# File lib/net/ssh/test/extensions.rb, line 127
        def select_for_test(readers=nil, writers=nil, errors=nil, wait=nil)
          ready_readers = Array(readers).select { |r| r.select_for_read? }
          ready_writers = Array(writers).select { |r| r.select_for_write? }
          ready_errors  = Array(errors).select  { |r| r.select_for_error? }

          if ready_readers.any? || ready_writers.any? || ready_errors.any?
            return [ready_readers, ready_writers, ready_errors]
          end

          processed = 0
          Array(readers).each do |reader|
            processed += 1 if reader.idle!
          end

          raise "no readers were ready for reading, and none had any incoming packets" if processed == 0
        end