The IContentLoader has nothing to do with A/B testing. You just need to create content variation and start your A/B teating. IContentLoader will only render the content variation returned.
Update on my previous reply.
Even you create variations of site setting item (if the setting item is set as datasource on some page to get it's content, but if you are getting site item via code then the A/B testing will not work).
And goals will not complete as you can not hit/visit the site setting item.
For more information see How it works Section
Feels like this could be a nice enhancement to the API though, to call a content item and specify if you should get the AB test versions of it, that was what i was hoping for, expecially with the focus on headless
Here I added an example to get the active test for a content. Hope this will be helpful.
So i have an interesting scenario.
We have a site with menu items defined via a settings page, separate to any content pages, these pages then load the menu as part of their loading logic via the IContentLoader,
The business would like to A/B a change to the menu item on the settings page, is it possible for content returned via IContentLoader?