# File lib/minitest/unit.rb, line 436
    def capture_io
      require 'stringio'

      orig_stdout, orig_stderr         = $stdout, $stderr
      captured_stdout, captured_stderr = StringIO.new, StringIO.new
      $stdout, $stderr                 = captured_stdout, captured_stderr

      yield

      return captured_stdout.string, captured_stderr.string
    ensure
      $stdout = orig_stdout
      $stderr = orig_stderr
    end