There is a test like that. It's called the "enablement" test and you must enable someone to build the thing in order to get a patent.
I'm talking more about the practical act of sitting down and reading a patent. They are long, boring, and filled with legalese. A patent may be 50 pages long, but the interesting part may fill no more than a few paragraphs and be described using nouns and verbs you've never heard before. It's completely possible to read a patent, look at the pictures, and still have no idea what the thing actually is.
It's essentially legal abstraction -- inventors and patent attorneys don't want to be pinned down to a particular interpretation, implementation, or embodiment.
I'm talking more about the practical act of sitting down and reading a patent. They are long, boring, and filled with legalese. A patent may be 50 pages long, but the interesting part may fill no more than a few paragraphs and be described using nouns and verbs you've never heard before. It's completely possible to read a patent, look at the pictures, and still have no idea what the thing actually is.
It's essentially legal abstraction -- inventors and patent attorneys don't want to be pinned down to a particular interpretation, implementation, or embodiment.