Source: Britney Wasn't Drinking

She may be partying, but she ain't drinking.

Although Tuesday night after a judge ordered her to undergo random drug and alcohol testing, a witness tells OK! that the pop star did not consume any alcohol, at least not during her stay at Hyde Lounge.

"People were drinking around her and doing shots and such but we didn't see her drinking," the source says.

Alcohol or not, it didn't stop the 25-year-old from having a good time with and and .

"She was definitely not in a sad mood by any means though. She was having a great time with everyone."

So it looks like Brit gets a passing grade...for now.