- When a user visits the donation page, a test group is selected for them randomly.
- Passing a parameter with the URL overrides the random selection for that particular case.
- Users are assigned to a test group for each of the currently running campaigns.
- The selection is being stored for later visits.
- If there already is a stored value, it is being used.
- Templates are displayed to users based on the stored/selected/passed value.
Currently, we have something like this in place for skin selection. This needs to be enhanced to be able to run multiple tests simultaneously.