terriann / Visual-Regression-Testing

From the 2019 WordCamp US - Visual Regression Testing Workshop by @ataylorme

Automating your QA with Visual Regression Testing Example Repository

This repository was originally an example from the workshop Automating your QA with Visual Regression Testing, presented by @ataylorme at WordCamp US 2019 in St Louis. The slides that accompany this repository can be found here.

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Important Note About This Repo Copy

Updated: Feb 20, 2020

The original repository was removed from GitHub by the author, but having found it to be an excellent starting point after attending the presentation in November, 2019, I pushed my local here since I had foolishly not forked it at the time of the presentation. I do not plan to do additional maintenance on this repository. If you have questions you should watch the video of the presentation, Andrew Taylor: Automating Your QA with Visual Regression Testing on WordPress.tv - part 1 and part 2

Update: Feb 20, 2020

Looks like @davidneedham is going to carry the torch on this presentation & repo! Look there for updates & improvements.

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Tools & Technologies

BackstopJS is used for the visual regression testing. The app itself is built with Node JS, commander.js, and Inquirer.js.

Prerequisites

You will need:

• A local development environment with Node JS/NPM
• A live, web-accessible WordPress site
• Another environment of the WordPress site above (e.g. local, staging, etc.)

Getting The Code

Create a new repository from this template and then either use Git to clone the repository or download the .zip file.

Instructions

After setting up the repository locally (see above) you will need to:

1. Run the command npm ci to download dependencies
   • This only needs to be done once
2. Run the command npm run start
   • Select the site you want to test from the list
   • Note: npm run start can be used anytime you want to run the app
3. Check out the results from the sample test
   • They should open in your browser automatically
4. Edit inc/sitesToTest.js
   • This is where the list of sites to test is stored
   • Try changing to one (or more) of your sites
   • nonProductionBaseUrl is your non-production environment (local, staging, etc.) URL
   • productionBaseUrl is your production site URL
   • Adjust pathsToTest, which is the array of URIs to test for each site
5. Edit inc/backstopConfig.js to adjust viewports, delay, hidden selectors, etc.
6. Run the command npm run start.
   • Select the site you want to test from the list

Troubleshooting

If you are having issues with the script hanging or BackstopJS taking a long time there may be headless Chrome instances that didn't close properly.

Try pkill -f "(chrome)?(--headless)" on Mac/Linux or Get-CimInstance Win32_Process -Filter "Name = 'chrome.exe' AND CommandLine LIKE '%--headless%'" | %{Stop-Process $_.ProcessId} in Windows PowerShell.