ATLANTA Joe Biden is pushing back at Republican assertions that he should take a cognitive test to disprove President Donald Trumps claim that the Democrat isnt fit for the Oval Office. Biden grew testy when CBS News correspondent Errol Barnett asked the presumptive Democratic presidential nominee about the matter in a recent interview. Why the hell would I take a test? Biden said. He then told Barnett: Thats like saying before you got on this program, youre taking a test whether youre taking cocaine or not. Im so forward-looking to have an opportunity to sit with the president or stand with the president and the debates, Biden said.