Masahiro NAKASHIMA

The theme can be changed and displayed to only logged in users.
The visitors of the website see your old theme while you are testing the new one.
Only the administrator of the WordPress site sees the new theme that can now be tested safely.
You can also use this plugin instead of “Theme Test Drive” plugin.

WP Theme Test

I have xdebug installed. There are two big Notices.

Threw two big PHP notices

The theme can be changed and displayed to only logged in users.

Presslabs

Olar Marius

Load one Theme for a specific user. You must set the theme from User Profile then logout and login again in order to take effect.
<h4>Github repository</h4>
https://github.com/presslabs/theme-per-user

Theme per user

Load one Theme for a specific user. You must set the theme from User Profile then logout and login again in order to take effect.

WP Theme Test vs Theme per user