Therefore, what is the PCR test testing for?

There are two piles of information here. By assuming SARS-CoV-2 DOES exist, you discover multiple internal flaws in the PCR. I've explored all of them in detail. If you back out of that exploration and realize the existence of virus is unproven to begin with, you're driven to the conclusion that the test results—positive or negative—are completely meaningless.

Performing the test would be on the order of building an outpost at the North Pole to count the population of passing nomadic desert tribes.

Or creating an auto safety bureaucracy that will examine deep-sea divers' oxygen tanks.

The PCR test looks for a piece of RNA in the swab sample taken from a person. That piece of RNA is PRESUMED to be part of the virus. But since you don't have an isolated purified specimen of the virus itself, all assumptions about that piece of RNA are null and void.

Therefore, the COVID case numbers, which are based on the test results, are meaningless. So are the death numbers.

The masks, the distancing, the lockdowns—which are based on case numbers—are absurd and destructive.