Question

One common case being the app has users and groups, only a user who is an admin of the group can add/remove users. I might have a controller action that goes “@group.add_member if current_user.is_admin”

It seems testing this behavior should be part of the model unit tests., because it’s a single piece of code responsible for a single task. But I’m not sure how best to include the fact that this method’s correctness depends on the controller. I was thinking:

1. One option is to redefine the model method to take an additional param for current_user, but
   that seems a bit ugly.
2. Another option is to test just “add_user” in the model and check ‘is_admin’ behavior in the
   controller test instead, though I was thinking this is a model concern.
3. Yet another option is to have this method be part of the User model
   instead of Group, so to be invoked as: “current_user.add_member_to_group” <– sounds like the
   responsibility for that functionality should be in the Group model
   though.

Thoughts?

Answer 1

Option 2 is fine.

Logic is safe:

• the model is responsible for it’s business

• the controller is the conductor