Why are we here?

[KevinM1]

Gotta hand it to you Stimbo, you are consistantly bright.
What is an autocomplete list?

Anyway, in the end, all will have been tested.
 Lucifer and the dingbat buddies of his failed their test.
We are living in our own test, and even in the Millennium Restoration, where life will be heavenly, it's end will be in a time of testing.

Beccs, when someone has an abundance of power, an expanse of distance or time, is a minor concern.
The concern is the result.
And we ain't there yet.

I have never received a coherent response from a Christian as to why, an omniscient being would need to 'test' anyone.

As I asked earlier in this thread, does anything happen that is not a part of God's plan?

If so, then he is not omniscient. If not, then he has no reason to test, since he already knows the outcome.

If there is another option, please let me know.

Moreover, tests are done in order to prepare the person taking the test for something in the future.  They're created to gauge our ability to apply previously learned material in a setting divorced from most real life consequences (except for the grades themselves).  Yet, by all accounts, the afterlife is a state of being so completely different from what we know, that any tests given here cannot have any impact on anything there.

Good character is wasted in paradise, and eternal, persistent torture doesn't afford one the opportunity to change.