Easily capturing response time metrics using the Watir-WebDriver-Performance gem

I don’t like long dedicated performance testing windows at the end of a project. I see response times as non-functional requirements, and like any other requirements, these should be tested as we’re going along. One way of effectively measuring performance testing is by conducting a response time test every time you do a build, if there’s a big degradation in performance: break the build!

A couple of months ago, Tim Koopmans released the Watir-WebDriver-Peformance gem. It’s aimed at providing a set of navigation timing metrics for Watir-WebDriver actions. This is a perfect solution to capture response time metrics, and it’s very straightforward to do (only works in Chrome and IE9 at the moment – no Firefox support).

require 'watir-webdriver'
require 'watir-webdriver-performance'

b = Watir::Browser.new :chrome

10.times do
  b.goto 'http://watir.com'
  puts "Load Time: #{b.performance.summary[:response_time]/1000} seconds."

This produces something like:

Load Time: 3.701 seconds.
Load Time: 0.694 seconds.
Load Time: 1.874 seconds.
Load Time: 1.721 seconds.
Load Time: 2.096 seconds.
Load Time: 0.823 seconds.
Load Time: 2.362 seconds.
Load Time: 1.008 seconds.
Load Time: 1.761 seconds.
Load Time: 2.066 seconds. 

List of available metric groupings

  • :summary
  • :navigation
  • :memory
  • :timing


The Watir-WebDriver-Performance gem is a great way to capture response time metrics from your Watir-WebDriver automated tests. By instrumenting your existing Watir-WebDriver automated tests that run regularly as part of a continuous integration process, you can start to capture and measure web application performance over time, and be alerted to the possibility of a change being introduced with adverse performance effects. Well done Tim!

Author: Alister Scott

Alister is an Excellence Wrangler for Automattic.

1 thought on “Easily capturing response time metrics using the Watir-WebDriver-Performance gem”

  1. This is a good gem and very useful for page load information. However in my case I was wondering if you had a solution to calculating response time of an action (not necessarily page load.) For example, I have a 1 page site. Everything loads dynamically. Jmeter does a fine job getting response times of the service calls, but since it’s not a full browser, I can’t really see how long it takes to run a AJAX request in IE vs. FF, vs Chrome… and so forth.

    Do you know of any solution to set timers on the actual Cucumber steps or actions themselves?


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