I had a guy come in and "test" my last litter of pups.  Basically at six weeks, he was looking for trained responses that I had not trained.  So he left disappointed, and so was I.  Here's the test, and my opinion of it.

Wing on a String
The wing on a string test supposedly shows pointing instinct.  You put a bird wing on a line attached to a pole.  If you haven't ever seen this, imagine a fishing pole with a wing for bait.  You yank the wing away each time the dog nears it until he stops and "points."  This is a classic parlor trick folks have been doing to sell puppies for generations.  I have seen a seven year old boy trained to "point" a dollar bill rigged similarly in under five minutes. 
I will likely do some wing on a string with these pups because folks think it's neat to watch, but don't count on it translating into pointing instinct.  You need to put live birds in front of the dog somewhere around 12 weeks.

Banging Food Bowls
The banging food bowls is supposed to show the pups aren't gunshy.  You bang food dishes together and the dogs are supposed to come running.  I don't think Pavlov's dog was a finely bred German Shorthaired Pointer, and he would have run to the bell.  All you are demonstrating with this test is Pavlovian response.  Banging bowl = Food time.  I have had gunshy dogs, none were afraid of banging food bowls.  Any dog who shows gun sensitivity and is properly introduced to the gun is showing a genetic problem.  Yes you can make a quivering mess out of any puppy, but it's harder to do with a dog with sound nerves.

We don't do any of this as it is annoying to us, to Dove, and to the puppies.  Banging food bowls and making loud noises at feeding time is a wives-tale that needs to go.  Properly introduce your pup to guns and pick a good breeder.

Rolling Ball
The rolling ball is supposed to illustrate prey drive and retrieving.  You roll a ball and see which dog is the first to catch it and pick it up.  What you are likely to see is which dog is the most outgoing or fastest.  I don't know how much prey drive and retrieving Corgi puppies have, but I have seen them run down a rolling ball.  It's the dominant pup that often gets to it first.  So perhaps, it does have some usefulness, if you are looking for a dominant pup.

It's going to be awesome weather for playing with puppies outside, and I'm sure a rolling bouncing ball will come into the picture.  Unless you are hunting tennis balls, don't count on this test to prove anything.

We'll probably have our Corgi breeder,  Diane Manocchia (http://ellisdogtraining.com/), come and do her puppy temperament test.  But I don't know how revealing that test is either.  It will be interesting to have the results to compare to what each dog eventually becomes.