green seed pod (fruit?) found in LA

Unfortunately, this is the only pic I have of this, as it comes from a friend. If only I had a pic of it sliced in half, the ID might be a lot easier. The original ID was 'an olive,' but it just doesn't match up for me. This was found in a yard in Los Angeles, possibly carried in by an animal.

 

Reminds me of the fruit of Acca sellowiana (see fruit pic here, where it is named Feijoa sellowiana)

 

It does look a bit like that. Thanks, Daniel!