There are a variety of tools to test your WordPress website’s accessibility.
The problem is that many of them require a live web page to check. And if you’re trying to get accessibility right, you most likely want to test your work before showing it to the world.
If you want to check a post or page for accessibility errors before publishing it, here is a plugin that might help you.
The Content Author Accessibility Preview plugin
It’s based on the work of Graham Armfield,