My roommate for the past 2 months has been inviting his uncle over every other day (and he often stays the night) and the uncle brings his dog. I didn't think anything of it first but one day the landlord came over midday and got super pissed because apparently he'd already told him not just no dogs inside, but no dogs on the property. Just last week the landlord (who is also a friend I've known for 2 years) told me to text him if ever the dog comes back. So today the dog was here, and after an hour I texted the landlord. Now my roommate is pissed at me.

AITA for doing what my friend/landlord asked me to do? Is this a case of I should have talked to the roommate first and hidden this from the landlord? I don't believe that is fair to expect that of me, I could be wrong though, what do you guys think?