@rockwizard :
Unfortunately, @chasebf has got it right mostly, especially their first response in this thread. I do think that the human mind is very complex and no tests could adequately judge its abilities. Having said that, adcom will definitely want to base their decision on something more concrete, e.g., your GRE score. Now, great thing about the US is this: it is super rich and can entertain all sorts of possibilities. Meaning, there are professors who will dismiss GRE right away. But, there are others who will NOT budge a tad bit if you could not pass their threshold.
Person