It seems to me that the point of mandatory reporting is to impose quarantining by force on people who wouldn't otherwise have done it. But if the test itself is

It seems to me that the point of mandatory reporting is to impose quarantining by force on people who wouldn't otherwise have done it. But if the test itself is not mandatory, then it defeats the purpose. i.e. If I have the choice between taking the test or not, and I know the test is going to report me if my result is positive, leading to consequences I see as negative, then I can just choose not to take the test. If I see the consequences of a positive test (quarantine, isolation, etc.) as necessary then I would just do it voluntarily and the government wouldn't need to step in.