How do you test for a viral infection? PCR is not nominal for that purpose, because it simply multiplies genetic material, and does not ascertain the source of that material.

I do understand how medical testing works, and Koch's Postulate is the necessary metric for such a test.

Let me know when you can provide a link to any test that can specify someone has been infected with SARS-CoV-2. Presently there is no test that does that.