There should be no such thing as peek a boo GFIs.
In modern houses kitchens have two, and sometimes three, circuits. Each is protected by a GFI receptacle.
One thing I always do in a home inspection is check the GFI receptacles.
All of them.
In the kitchen I make sure that everything that is supposed to be GFI protected is in fact protected.
For example, if there is an island, it should be protected.
And the refrigerator should NOT be protected!
So I look around.
And that's an easy check!
I plug in my device which evaluates the circuit and push the "test" button!
When I see the lights go out and hear the receptacle snap, I turn it back on and move to the next.
In this kitchen I heard the snap, but could not find the receptacle.
I looked all over! GFI receptacles are sometimes put in what I consider to be odd places.
Behind this kitchen wall is the laundry room. I thought, "Did they put the GFI in the laundry room?"
But after looking there, no, they did not.
Where is it?
Look at the photo above. Can you see the edge of the receptacle cover behind the stuff in the cabinet?
Moving the stored things out of the way, I found the receptacle!
IT'S INSIDE THE CABINET!
I have to confess to never seeing that before!
It turns out that the builder in this house left a large portion of wall without cabinet coverage, favoring a very small desk instead.
The builder also left them a tiny pantry.
So these homeowners decided to add another cabinet to the kitchen where the desk was located.
This is fine, even a smart thing to do. An additional kitchen cabinet is rarely a bad thing! But while adding it they covered up the receptacle on the end. Don't plug in the toaster!
You can see the work was probably done by the homeowner as the receptacle opening is roughly cut.
My recommendation: when GFI receptacles are tested, they have to be turned back on. Sometimes they are very difficult to find! In one house I could not find it and it turned out to be buried behind drywall in the "finished" basement! Fortunately here we were able to find it, albeit in a very odd place!