Visual Regression Testing is basically comparing screenshots from two different states – the before and after state, after an event has occurred.
So how does this apply to your WordPress site?
Let’s say you are updating your theme or plugins, it’s something almost all WordPress webmasters or admins do on a regular basis. Once you have performed the updates, you will want to know if something has changed on the front end of your site. Why? Because you don’t want your client or customers coming back to you angry when they find out that something broke during the updates which you performed.
How can I know if something changed on my sites after updates?
This is where Visual Regression Testing comes in handy – comparing the before and after states will let you know if something has changed down to an element moving one pixel to the left. Any change on the front end will be visible to you and you can then decide if it’s something which needs attention or not. If something broke, then you will of course want to debug or find out the cause of it breaking.