I do stuff like that a lot too. There is nothing wrong with you daydreaming during a test! Seriously, there is something wrong with the test. I find that a lot of people with adhd get bored easily and really can't help it. Now that I'm out of school and I look back to the school assignments I had, I realized that honestly most of them were busy work and really not important to me. They weren't the experiences in life where I learned the most or even the ones I remembered. People with adhd a lot of times can't focus on things that they don't truly care about or find value in even if they want to. It wasn't like I wanted to be zoning out during my homework. If I could have just focused for a little I could have finished it way faster and then moved on to something I did want to do but of course I was always spending hours and hours staring at papers in the library trying to make myself focus. I literally couldn't focus on things that I really didn't see value in. I have the ability to intensely focus for hours I things I love. This is called hyperfocusing. I can never control when it will happen it just does and I get in the zone. Just like when you get in the zone with your day dreams. ADHD isn't the inability to focus, it is the inability to regulate focus. A kid with ADHD can one day not be be able to focus on something no matter how much they are trying but then another day be able to focus so intently on something else that they lose all track of time and can't shift their attention to the things they need to get done. What might be good for you long term is to find a job or life path that you really enjoy. I'm out of college now and I do jobs like farming, working at ski resorts and am looking into guide jobs and state parks. It doesn't have to be that but things that are more hands on or that you are really interested in. Have a fun and exciting life. I find that my ADHD nature isn't an hindrance in a lot of the jobs I am looking at now, it is often a benefit. I can multitask easily and am good with my body and have good reflexes. I barely read or write and I'm okay with that. Do what feels right to you. You are just different.

Also I used to have intense day dreams like that. I would make up whole characters that for months I would play with. I would keep adding to the story. Whenever I sat down I'd pick up where I left off. I'd disconnect from the room and be like I was living through those characters. Now that I have changed my lifestyle a lot I find that I am zoning out less and doing engaging things more. I hang out with people who are really interesting and discuss things I enjoy talking about. And friends who are always up to go out on an adventure and do something random and fun. My work is usually very engaging and enjoyable so I see no need to day dream because I love the life I am experiencing.