Our ability to pay attention has deteriorated over time. People are quick to go to a competitor’s site if a page loads poorly online. They don’t have time for slow websites. Businesses that fail to recognize this risk lose a significant amount of money as a result of unfavorable customer feedback.

As testers, we must ensure that our users have a great experience. It’s not enough to check that requirements work as they should. We must make certain that performance and user experience are not harmed. And none of this can be put off any longer.

On the back end and on the front end, performance testing is commonly carried out. When several requests are submitted from users at the same time, you must ensure that the servers can handle the demand. Users will receive the dreaded 503 error if they are unable to do so. Load-testing tools like JMeter, K6, and Gatling can help you predict how your servers will perform.

When performing front-end performance testing, servers may return a response inside the desired time frame, but this does not guarantee that your users will see it right away. Performance is also affected by how various browsers handle payload data from servers. JavaScript adds interactivity and functionality to websites, but it may also be a drag, especially if it isn’t optimized and prevents content from being rendered completely. Cascading style sheets are the same way.

Back-end testing also includes a number of tools to aid in the evaluation of your website’s performance. Google Lighthouse is one of the most popular, and it may be used as an extension for Cypress, a JavaScript-based end-to-end tool for testing web page performance.

Google Lighthouse

The open-source Google Lighthouse tool can be used to check other aspects of a website besides performance, such as accessibility and SEO. Lighthouse is simple to use: you don’t need any technical knowledge to begin auditing your website’s performance. Lighthouse can be used in a variety of ways, but the simplest is to utilize it as part of Chrome Developer Tools, which is already installed. Simply launch Developer Tools and select the Lighthouse option to begin the audit. Google Lighthouse is demonstrated in the images below.

Lighthouse calculates a set of scores based on verifying parameters like “initial contentful paint,” “biggest contentful paint,” and “time to interact” when the audits are completed. The article “Lighthouse Performance Scoring” explains how the score is calculated and what the different measures mean.

Integrate Lighthouse early in your development and testing pipelines to get the most out of it. It will be feasible to determine which code modifications contributed to changes in your performance ratings once you and your team have decided on the performance thresholds to use.

Cypress and Google Lighthouse

The command-line interface is one option to operate Google Lighthouse, which gives you and your team additional flexibility. Another possibility is to expand Cypress with the custom plugin cypress-audit to cover web page performance.

Yes, Cypress may be extended to include web page performance. Cypress is perhaps one of the most popular testing frameworks available, and one of the things I enjoy about it is how readily it can be extended to encompass additional sorts of testing. With its range of available plugins and connectors, I’ve used Cypress to test UI functionality, make API endpoint calls, and test for accessibility and visual elements. So, when I saw a plugin for integrating Google Lighthouse with Cypress, I decided to give it a go.

Marvin Frachet designed the plugin, which allows you to use your current Cypress tests while also adding new commands to check the performance of any pages you choose.

Although it’s a new plugin, its NPM weekly downloads indicate that many engineers are using it.

If you run the cy.lighthouse command without any arguments, the test will fail if any of Lighthouse’s default categories have a reported score of less than 100.

After the test is completed, you should get a log that shows any categories that fell below the preset level. An example of a test run is as follows:

How to get started

To get started, download and install Cypress and cypress-audit. “Web Performance Testing with Google Lighthouse” is a blog post that walks you through installing the packages you’ll need, as well as a GitHub repository you can clone.

The back-end and front-end performance testing can be quite beneficial. You may incorporate performance testing earlier because of the number of performance testing tools available. Google Lighthouse makes it easy to track the performance of your websites by measuring critical indicators, and Cypress makes it easier to test for performance.

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Also Read: https://www.guru99.com/software-testing.html