I was at my mom's house today and she has a tree growing in her garden with the shape of a young crabapple tree but has bluish/purple berries. They are the diameter of a large pea with a few large seeds in each. The juice, when split open, reminds me of blueberry juice and stains your skin the same. I wasn't sure what it was so tasting it was out of the question. The berries aren't in clusters;they are singularly hung, but near one another. I don't have a pic, sorry.
"a few large seeds in each" - so not a cherry (a single-seeded drupe) I think it'll need a photo to make it identifiable.
Agree with Ron. Note: mildly poisonous - eating a berry won't kill, but will give some unpleasant effects, including violent diarrhoea. But the foul taste would probably make you spit it out before swallowing, anyway.