To me it looks like a yellow variety, since yellows have those red pigmented stems, and purples I think have green stems. I have two yellow flavicarpas, which have those such redder stems ,compared to those of my purple edulis plants, which are plain green. The flower should be a hint as to the general fruit color (yellow or purple). My purples bloom with visually different flowers, compared to the one in your pic. As roblack suggested ,polinate it with its own pollen firs, just tho know if its self fruitfull. The purple ones I have ,were seed started and set fruit on their first flowers, with their own pollen, purples are generally self fruitfull ,so if your plant does not set fruit when u self pollinate a few flowers ,then it needs a partner...