Huh! I'd not heard of the "shopping cart test", despite having thought along the lines of its essence scores of times over the course of my life....
I worked at a grocery store briefly in the days of my youth, and rather enjoyed collecting the carts - amidst thoughts of "What a bunch of fucking lazy asses!", of course. But stringing long chains of them together, and muscling them places while surrounded by both stationary and moving people/vehicles seemed a fun challenge.