During a news conference Wednesday evening, President Trump said: "We don't have to test the entire state in the Middle West or wherever they may be. We don't have to test the entire state. I think it's ridiculous. A lot of those states could go back [to work] right now, and they probably will."
He's correct that the entire population of a state does not need to be tested right now. However, all 50 states do have cases, and those small- and medium-sized outbreaks may be growing exponentially.