"I think there's been some rumours before and nothing's happened," Brawn told a news conference after the first day of practice for Sunday's Canadian Grand Prix.
"I think we should say let's wait and see what the tribunal find and then we can take it from there. It was my decision to do the test so that's a fact."
Brawn also shot back at suggestions the tests were conducted secretly.
"It was a private test," he said.
"It wasn't a secret test. Anyone who believes you can go to Barcelona and do three days of testing, or 1,000km of testing, and not have anyone become aware, is very naive. Sporting integrity is very, very important to us, very important to Mercedes. And, I think when the facts become apparent, people can make a better judgment of the situation."
While Brawn defended himself, Pirelli boss Paul Hembery, who was also scheduled to appear at the conference, pulled out on legal advice.
"If ever you're going to a tribunal any lawyer will tell you at that point you have a formal process to follow, which we're happy to follow," said Hembery.