How exactly does one test pickups and preamps for acoustic guitars (I assume they're sold together??)

I mean if you're trying out different pickups they're going to be on different guitars and therefore incomparable. How do you test them in the shop?

Any help is greatly appreciated, especially from someone who's got experience with buying their pickup and guitar separately.

I know it's just easier to buy one with it already installed but I really like the sound of this one guitar acoustically and hate it plugged it, so yeah, thanks for your responses
It's hard to test them. You either need to find someone you know who already has them, or you need to see if you can test them out at the store. I was lucky enough to find someone who had the same pickup that I bought(the LR Baggs M1 Active).
- Art & Lutherie Cedar CW (SOLD! )
- Martin D-16RGT w/ LR Baggs M1 Active Soundhole Pickup
- Seagull 25th Anniversary Flame Maple w/ LR Baggs Micro EQ

Have an acoustic guitar? Don't let your guitar dry out! Click here.