Acca sellowiana, syn. Feijoa sellowiana (Pineapple guava).
Evergreen shrub that is drought tolerant, salt tolerant, takes pruning, produces beautiful flowers whose fleshy petals are edible (they have a sweet taste) and edible fruit. I grew my bushes from seed about 14 years ago and have seen no sign of either pests or diseases in that time. What more could anyone ask of a plant?