As a rule of thumb, I generally say that your rest is interrupted if you attack, are attacked, cast a spell, flee/run, or engage in more than 6 turns (1 hour) of sedentary activity.
I’m just envisioning a slightly bored, slightly irritated, groggy mage popping her head out of a tent at the sound of combat, seeing that the fighter has it “taken care of”, then calmly retreating into the tent and falling asleep.