For the same reason you'd quit walking in your house at night without turning on the lights after your dog develops a bowel problem. Testing helps us see the p

For the same reason you'd quit walking in your house at night without turning on the lights after your dog develops a bowel problem. Testing helps us see the problem and deal with it before we step in it and spread it around. Isolating is like putting the roomba on a shelf for a while. Without taking that step, no amount of turning on the lights will save you. Both strategies are important and complementary.