Automated Accessibility & Performance Testing for Web Based Applications

The below document details out how to setup and perform Automated Accessibility & Performance Test along with generating detailed Test Results using Lighthouse. It also includes the setup required to perform this automated test on a list of URL's as a batch.

Prerequisites:

• Nodejs
• Install Google Lighthouse by Node.js

Installation command line:

npm install -g lighthouse

Once it’s completed, you can try running this command line

lighthouse https://www.google.com

This will generate the results in html (default) format. The location of results will be displayed on the command window.

Customizing lighthouse:

Use below command line for all customization options

lighthouse –help

Headless & Quiet mode:

If you want headless and without log in command line

lighthouse --quiet --chrome-flags=”--headless” https://www.google.com

Categories:

It is also possible to choose which categories you want to report on. Following categories are available to be included in the report:

• Performance
• Accessibility
• Best Practices
• SEO
• PWA

Example with default all categories.

lighthouse --only-categories=SEO https://www.google.com

Example for multiple categories:

lighthouse --only-categories=SEO --only-categories=performance https://www.google.com

Desktop Vs Mobile

We can simulate both Desktop and Mobile behavior of application under test.

--emulated-form-factor=desktop

--emulated-form-factor=mobile

Generating Report for Multiple URL’s

We can also build a batch file which can generate report for multiple URL’s and help save time.

• Create a batch-file with your any text editor. Paste the following code into it:

@For /F "UseBackQ Delims=" %%A In ("URLS.txt") Do @LightHouse "%%A" --quiet --chrome-flags="--headless" --emulated-form-factor=desktop -disable-storage-reset --throttling-method=provided -- preset=perf –

• Create text file with list of all URL’s you would like to be part of batch test.

1. Run the script. Go back to the command prompt and navigate to the folder where the two files were saved.

cd <Nav URL>

Example with folder:

cd C:\Users\SourabhGoel\Download\Lighthouse\

All you should need to do now is running the command below:

<name of batch-file>.bat

Working with Web-pages which require Authentication:

There are multiple options to handle the authentication.

Puppeteer - a browser automation tool - can be used to pro grammatically setup a session.

Launch a new browser. Navigate to the login page. Fill and submit the login form. Run Lighthouse using the same browser.

Below are Sample Test Results

References:

• Github
• Lighthouse https://developers.google.com/web/tools/lighthouse

Sourabh Goel

TECH-Sales-Marketing & Strategic Projects

P I M C O | Newport Beach, California

Please consider the environment before printing this article