Not sure I accept it as a test, because with the same points in place that you already noted - he would know what the result would be there as well.

In our world the device in play is called reverse engineering. How one takes apart something already built to see HOW it was built. I think whoever was involved in writing the stories of the bible had this issue to contend with. How do we show a principle at work?

So for me it begs the question, is this a story about what was or a story about what we would like to see? I think the latter is more likely.

Interesting stuff.