Performance testing; What, why, how and when? | Digivante

Performance testing; What, why, how and when?

by Amy Montague, 27th November 2019

Website performance testing has never been more important than in today’s hyper-competitive world.

Because, as Mae West once memorably put it;

“An ounce of performance is worth pounds of promises”

Taking the shine off digital transformation

The shiny digital promise of unrivalled bargains attending Black Friday, Cyber Monday, Amazon Prime Day and other much-hyped digital retail events, can only be realised if the capacity, availability and responsiveness of a site or app can match the demands being made of it.

In fact, research shows that more than half of visitors will leave a web page if they’re forced to wait longer than three seconds. At the same time, 30% of site visitors expect a page to load in one second or less, while 18% expect a page to load instantaneously. Compare that to five years ago, when only 5% of consumers expected a one second or less page load.

So, when the speed and quality of every moment of a visitors’ digital experience impacts your potential to convert them into customers – as well as their perception of your entire brand – its ability to perform at all times must become a central concern.

What is Performance Testing?

Performance testing is an umbrella term for a number of different tests that can be conducted to evaluate a website’s load times and responsiveness under different conditions. Performance testing examines stability, scalability, reliability and the speed of your site. But different kinds of performance tests can check for different capabilities and the ability to fulfil different business needs. Load testing ensures a site or app can comfortably deliver against expected levels of traffic, while stress testing tries to discover their breaking point so you can plan for unexpected spikes and unprecedented visitor volume.

How to promise and perform

There’s no way round it, in today’s market place we’ve got to promise AND perform or risk losing customer’s loyalty and trust for good.

It’s no good creating ever more exciting website features and user experiences if you can’t deliver those experiences speedily and seamlessly.

The standard usability and functionality tests that you might typically perform before releasing software will not predict how your site will respond to sudden traffic spikes or even under normal conditions when you move to production.

Only performance testing can give you the confidence that your site is equal to the most extreme challenges of the e-commerce calendar, or the information you need to act to prevent a crisis.

graphic of two people examining a mobile

Types of performance testing

Here’s our guide to what all the performance testing jargon means and when each kind of testing might be relevant for you.

  1. Load testing checks that your site will be able to host all expected levels of traffic. It provides insight into your application and the system’s behaviour under specified conditions. For example, it might test what happens when concurrent users perform a specific number of transactions within a set duration on your website. It is possible for a load test to focus on different parts of your system, like the checkout webpage, to give snapshots of your capacity to comfortably serve your customers at the most critical times in their journey.

Load testing is something you should be doing as a matter of course and all the time, particularly if you are working in an Agile state of continual software delivery and deployment.

  1. Stress Testing deliberately tries to break your web applications by incrementally increasing the number of users on your site. This kind of test can determine your website’s robustness in times of extreme load, and then how it recovers afterwards.

There are two types of stress testing that you’re likely to hear about:

  1. i) Spike testing.  Flash sales, Black Friday, new releases – the modern retail calendar is peppered with e-tail red-letter days.  Spike testing warns you if a sudden and extreme spike of traffic during these events is likely to break your website or expose any bugs.
  2. ii) Soak/endurance testing. These testing scenarios check your website’s ability to deal with expected, continuous heavy loads and how it will recover from them afterwards.

KPIs from these tests might include the effect of extreme visitor volume on memory, speed, security issues and data loss or corruption.

Make sure you can see the results

The reliability and sophistication of the reporting platform you have available to your developers is key to determining how useful this kind of testing exercise is. The more fine-grained your reporting capability is, the more value you will be able to extract from it.

Effective stress testing should let you isolate variables through a series of different tests in order to determine the point of failure for each.  Such tests may include:

  • Isolating all traffic to one particular geographic region
  • Isolating performance across multiple browsers, platforms and devices
  • Isolating the speed of image loading on specific devices and browsers

Determining the point at which each component in your infrastructure will fail is a critical part of ensuring your web application is able to scale.

Performance testing with the right tools gives you the data you need to make the right decisions, protecting and increasing your revenue and reputation, even in the most unpredictable phases of growth and change.

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Amy Montague

Article by Amy Montague

Amy is Digivante's marketing executive and content creator. She focuses her efforts on planning and producing bespoke content pieces, encompassing social media, Digivante's online resources and industry-leading articles.

About Amy

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