There is a VERY important fact being diluted at the moment RE Covid testing. In asymptomatics, a negative test result only tells a person they do not have detectable SARS-CoV-2 ON THE DAY TESTED. It is not a clean bill of health badge.
symptoms arising in the few days after a test should be dealt with immediately as suspected Covid and another test performed. Even in the absence of symptoms after test, it does need remove the need for face coverings, distancing, and appropriate behaviour.
In an asymptomatic person, a negative test result is not an "I'm Covid free" badge. It is a confirmation you do not have detectable infection that day. A negative test in an ill person DOES mean you dont have Covid, but still have an infection of some sort
and if you have an infection that isnt Covid, stay at home anyway so you dont pass it on and lead to lots of people worrying they might have Covid when they dont