What exactly is a horrible vocal range?

I dont have enough vocal range according to this test because I cant sing low or high enough

What do you mean enough? You have to be more specific. Do you have less than one-and-a-half octaves? Then you need to develop your foundation, yes. If you have two or two-and-a-half octaves, you have plenty of range and you can sing most songs.

The amount of training that goes into getting to a point where someone can sing while doing anything other than stand or walk around on stage takes a LOT of training. Just because you can't doesn't mean you're not artist material. There are more famous singers who could do a full concert from a stage that's only 2'x2'. Hell, I'm old enough to remember when everyone in the United States went on a Gregorian Chant kick, where every vocal was allowed, maybe, three notes per song.

Also, if you're talking about writing your own songs, then whatever range you have is perfect. Even if you only have a one octave range, there are 12 notes you have at your disposal. Play around with all of the ways you can sing the notes in your range and then go from there. As a kid, Pete Townshend couldn't afford guitar strings. When a string broke, he would restring his guitar so the ones left were closer together. He's attributed that in interviews as one of the reasons for his musical style.

All that's to say, while you might not have the tools necessary to sing along with your favorite songs in their native keys (I sound like I'm being stabbed to death every time I try and sing anything by Bruno Mars), knowing the notes you CAN sing is all you need to write your own songs. As you keep practicing, your range will grow as your instrument gets stronger and you discover new things.

And if the music genre you love isn't written in your range, then congratulations on being the first!

Great answer, @Josh M !