# File lib/minitest/benchmark.rb, line 83
    def assert_performance validation, &work
      range = self.class.bench_range

      io.print "#{__name__}"

      times = []

      range.each do |x|
        GC.start
        t0 = Time.now
        instance_exec(x, &work)
        t = Time.now - t0

        io.print "\t%9.6f" % t
        times << t
      end
      io.puts

      validation[range, times]
    end