Well, if they also preclude the use of an autopilot for this test, then sure, going hove-to to reef would be the way to do it. But with an autopilot--why? I reef all the time single handed and never put the boat hove-to to do it. It's an extra and unnecessary step.
Again, no doubt we can come up with ad hoc situations in which this makes sense--such as an ASA test with artificial constraints--but as generic advice for single handers?
Why? Because I have sailed with and autopilot long enough to sail with one that did not work.
Hove-to is a tool, just like the AP is a tool. Is one good and the other bad? One useful and the other not useful? Nope, they are just different. I can remove most any bolt with a combination wrench so does that mean that I do not ever need to use a rachet and socket or even an adjustable wrench? Nope, I have lots of tools at my disposal many of which do the same basic thing, but each has its own best use. Sometimes the choice comes down to which was is closest at hand.
I don't usually hove-to as often now that I have a reliable autopilot but still practice it frequently because those things like to quit at the most inconvenient of times. My previous boats did not have an AP and it was the rare day of sailing that I did not do it several times.
On our boat, pretty much anytime anyone needs to use the head while we are sailing, we hove-to because it is much nicer to use a stationary mostly level throne that is it to use one that is leaning at 15º to 20º and bouncing up and down. Those conditions are great for sailing but not much fun for taking a leak.
When we are doing the weekly can races, between race starts, I will typically sail to to starboard of the committee boat and hove-to and the whole crew takes a break as we slowly drift to leeward.
Most boaters I have run into who say that hoving-to is not useful as a basic sail handling technique, have never taken the time to try it in a variety of conditions. For many sailors, it is considered a "storm tactic" of last resort so is only useful for extreme emergencies. I suggest that people first try it on a day with 5-kts of breeze with full sails up and then work up from there.
The only wind conditions that I cannot hove-to in is dead calm. Even in then I will trim the sails tight and lock the helm the other way. It is not uncommon for me to bob around in the middle of the cove reading a book with full sails up. When the wind starts to fill in, Papillon will wander around for a bit before settling into a hove-to because once the sails and rudder are set, that is where she is going.