> [1] A test for non-obviousness: does an implementor care to look at your patent or reverse-engineer your implementation, or is a description of what the invention does sufficient?

This seems like a wonderful test of obviousness to me.

However, the "what" could be: "A method of reducing the number of online sales that are attempted but somehow aborted".

The "solution" of having a single click to purchase, in the context of cached purchase info and permission, might not be obvious to everyone working on that problem. (Even though it might be obvious in hindsight - which is not a barrier to patentability.)

That "solution" is specific enough to not block other's from solving the same problem (avoidance of aborted purchases) in via different methods.

That would be the approach I would use to defend single-click against your test. (Not a lawyer, no special legal expertise, just working through the logic as I can see it.)