At the moment you can only ask for a test if you think you have the virus and belong to certain group keyworker or over 65 etc. Therefore that would have to change to include all those sent a positive signal. Then there is an issue with incubation period as we were told it takes 14 days to develop with some people.
What we need is your own test kit pack where you can test yourself once a day and get an instant result, like a pregnancy test. You could take your result with you when you leave the house and show it to relevant people who may ask such as hair dressers who come into close contact with you. The result could be physical or on your phone so everyone can be involved. People who have had the virus would carry a certificate too, tested with anti body kit - if its proved you can only get it once.