Exploration Through Example

Example-driven development, Agile testing, context-driven testing, Agile programming, Ruby, and other things of interest to Brian Marick

191.8

⇒

167.2

⇒

186.2

183.6

184.0

183.2

184.6

Thu, 13 Oct 2005

A Watir win

At PNSQC, Michael Kelly gave a talk. Among other things, it covered converting functional test scripts into performance test scripts. He gave examples using several tools, one of them Watir.

As he described how little of the test script had to change to make it a performance test script, I realized that there was a way to make it require no changes. I didn't quite finish a demo during his talk, but I did shortly after. Here's an example:

Load (a fake version of) Watir, get an object representing IE, and ask it to go to a URL.

irb(main):001:0> require 'watir'
=> true
irb(main):002:0> ie = IE.new
=> #<IE:0x329144>
irb(main):003:0> ie.goto('url')
=> "here's a bunch of HTML"

(I faked out Watir because I didn't have net access and, anyway, this machine is a Mac.) What you can't see in the above is that goto delays a random number of seconds before returning.

Now I want to run the same "test", timing all gotos.

irb(main):004:0> require 'perf'
=> true
irb(main):005:0> IE.time(:goto)
=> nil
irb(main):006:0> ie.goto('url')
1.000129
=> "here's a bunch of HTML"

It took just over a second.

Here's the code. Mike will be seeing about getting something like it into the Watir distribution.

class IE
  def self.time(method)
    method = method.to_s
    original_method = '__orig__' + method
    new_def = "alias_method :#{original_method}, :#{method}
               def #{method}(*args, &block)
                  start = Time.now
                  retval = #{original_method}(*args, &block)
                  puts Time.now - start
                  retval
               end"
     class_eval(new_def)
  end
end

Take that, WinRunner!

## Posted at 15:08 in category /ruby [permalink] [top]