How to serve all existing static files directly with NGINX, but proxy other requests to jetty?

Question

My question is similar to How to serve all existing static files directly with NGINX, but proxy the rest to a backend server.

different is that my site directory structure looks like this:

/nginxRoot/test/js        
/nginxRoot/test/images  
/nginxRoot/test/html
........       

So the site root isn't "/nginxRoot/" but "/nginxRoot/test/"

I want to nginx to serve all static files that have been put at directories:js,images,html,and proxy other requests to jetty,I have tried:

location ~ ^/test/(.*)\.   (jpg|jpeg|gif|png|js|ico|css|zip|tgz|gz|rar|bz2|pdf|txt|tar|wav|bmp|rtf|js|flv|swf|html|htm)$
{
    root  /ngixRoot/test;
}

 location ~ ^/test/(.*)$ {
    proxy_pass http://127.0.0.1:8080/$1$is_args$args;
    proxy_redirect off;
}

All requests to jetty works,but all requests to static files don't,I doubt they are forwarded to jetty also,is that true?how to fix this problem?

Update Followed the suggestion of @Alexey.Ten

I tried

location ~ ^/test/$ {       
   try_files $uri $uri/ @jetty
} 

location @jetty {
    internal;
    add_header X-Local true;
    add_header X-Cache $upstream_cache_status;

    proxy_pass              http://$http_host:8080$uri$is_args$args;
    proxy_cache             one;
    proxy_cache_key         backend$request_uri;
    proxy_cache_valid       200  1h;
    proxy_cache_use_stale   error timeout invalid_header;
}

but nginx can't be started any more