roommate problems

Amber • Daughter of the King, Wife, momma to three boys, doggy Momma 🐶❤️
So I moved in with someone I barely knew just until I can afford to live on my own. I have a dog, she's super cute. She's a beagle mix. She's never bit nor growled at anyone before. EVER. She's all bark but no bite. She'll attack you with kisses. Anyways, I work two jobs and she stays in my room when I'm at work so she doesn't bother my roommate. While I was at work the other night, my roommate told me my dog attacked her friend. 
I'm confused on what I should do. I was sitting down in my bathroom getting ready when my roommate walked in today and she growled at her which she has never done before. We were out of town all weekend just to make sure she stayed away from her. There is no way my dog made the hole (I honestly think it was already there)/ attacked UNLESS she was provoked. I'm a firm believer in that dogs can judge ones character. What should I do?