post=assert_queries(2){Post.find(post.id,:include=>{:author_with_address=>:author_address})}# find the post, then find the author which is null so no query for the address
post=assert_queries(1){Post.find(post.id,:include=>{:author_with_address=>:author_address})}# find the post, then find the author which is null so no query for the author or address