Joe Biden bristled at a question about whether or not he has taken a cognitive test, asking an interviewer Tuesday morning whether he would pass a drug test and stumbling over his words several times in the course of one minute.

During an event with the National Association of Black Journalists, CBS News’ Errol Barnett asked if Biden has taken a test that would assess his mental fitness, and Biden snapped, “No, I haven’t taken a test! Why the hell would I take a test? C’mon, man!”

Biden then challenged Barnett, “That’s like saying you, before you got in this program, if you take a test where you’re taking cocaine or not, what do you think? Huh? Are you a junkie?”

The presumptive presidential nominee went on to boast of his mental acuity and readiness to debate Trump — but stumbled with word order, word choice, and pronunciation multiple times in the same sentences.

“I’m so forward looking to have an opportunity to sit with the president — or stand with the president — in debates,” he insisted (emphasis added).

“I am very willing to let the American people judge my physical, mental fil–my physical as well as my mental fil–fitness,” he concluded.

In May, Biden caused controversy when he told Breakfast Club co-host Charlamagne tha God that “you ain’t black” if voters go for Trump.

“If you have a problem figuring out whether you’re for me or Trump, then you ain’t black,” Biden said.

“It don’t have nothing to do with Trump, it has to do with the fact — I want something for my community,” the radio host shot back.

Biden claiming he has not taken a cognitive test is a reversal from a statement he made in June.

“I’ve been tested and I’m constantly tested,” Biden responded when he was asked by a reporter about a mental assessment.

“All you’ve got to do is watch me, and I can hardly wait to compare my cognitive capability to the cognitive capability of the man I’m running against,” he said.

Former White House Physician Dr. Ronny Jackson has said President Trump “aced” a cognitive assessment in 2018.

“If (Trump) goes head-to-head with Joe Biden cognitively, there just wouldn’t be much of a comparison. It would be very one-sided,” Jackson told The Kyle Olson Show.

“They cannot afford to put Joe Biden on the stage side-by-side with President Trump. It will be an unmitigated disaster for their party,” he said.

Kyle Olson is a reporter for Breitbart News. He is also host of “The Kyle Olson Show,” syndicated on Michigan radio stations on Saturdays. Listen to segments on YouTube. Follow him on Twitter, like him on Facebook, and follow him on Parler.