My roommate gave him Herpes

Okay so I am entering my junior year of college and my best friend and I have been friends for years any ways. We have separate apartments so I have my issues with my roommate and she has hers. She has one roommate and I have two.

So we're having a little bit of girl chat and she's like girl my roommate told me she has Herpes. I said FUCK YOU MEAN! She was like yea Herpes. She's been fucking two other dudes, she gave it to her boyfriend and another random dude.

Then I was like did she tell her boyfriend that she cheated because she shouldn't do that especially with someones health. My friend said she told the other guy and not her boyfriend.

So my friend wants to tell her roommates boyfriend that he should get tested but she doesn't want their to be any conflict between her and her roommate.

What should she do?