NGINX try_files + alias directives

I'm trying to serve request to /blog subdirectory of a site with the php code, located in a folder outside document root directory. Here's my host config:

server {
    server_name  local.test.ru;
    root   /home/alex/www/test2;

    location /blog {
        alias   /home/alex/www/test1;
        try_files $uri $uri/ /index.php$is_args$args;

        location ~ \.php$ {
            fastcgi_split_path_info ^(/blog)(/.*)$;
            fastcgi_pass unix:/var/run/php5-fpm.sock;
            include fastcgi_params;
        }
    }
}

And I get for requests like

wget -O - http://local.test.ru/blog/nonExisting

just a code of index.php file from /home/alex/www/test2/ folder.

However, this config:

server {
    server_name  local.test.ru;
    root   /home/alex/www/test2;

    location /blog {
        alias   /home/alex/www/test1;
        try_files $uri $uri/ /blog$is_args$args;
        index index.php;

        location ~ \.php$ {
            fastcgi_split_path_info ^(/blog)(/.*)$;
            fastcgi_pass unix:/var/run/php5-fpm.sock;
            include fastcgi_params;
        }
    }
}

gives me index.html file from /home/alex/www/test2/. Please give me a clue - why? And how can I force NGINX to process /home/alex/www/test1/index.php instead?