Tests of a (future) supergirl

Hi guys, I'm curretly toying with a new idea for a self-contained story, the basics are that a superheroine (possibly the only one in the world) is looking for a sidekick/replacement after realing that even with all her powers there's only so much she can do for the world. Now I'm really struggling to put together a serie of credible tests/challenges for the "recruits", so I'm here asking for a little help.
What kind of parameters do you think these tests should measure?
Do they have to be life threatening?

Keep in mind that the himmick that will gave the new supergirl her powers isn't for the feeble, the enhanceing process is likely to be quite painful and taxing for the orgamism, so all the recruits have to be in good physical shape.

I'd say a combination of mental, physical, and the very last one being the life threatening one. Maybe that last test has the candidate doing the 'heroic' thing and risking their life without thinking about it.

This is more or less the same outline I was thinking about.

The life threatening test would have to be one the candidates are not aware of, so as to prove their worth in a real life situation.

I haven't think about this, but it makes sense.

Right now I'm thinking about making this a short interactive story, like Argo did with Late Night Smackdown