You're sort of setting yourself up for hardship if you are deploying a Symfony app to a host that does not allow SSH - for instance if you want to rebuild your cache you will have to manually nuke your app/cache/* dirs?
To answer your question directly, if your Symfony project is in /www/test/ then Symfony's web directory is /www/test/web so you need to use a url like:
http://foo.com/test/web
For completeness, try accessing the explicit url - /test/app.php and /test/app_dev.php respectively. If you receive a Symfony error page in either case you know you are on the right path at least.
Edit #1
Something to point out: your project and configuration files and may be readable with this deployment scenario - which is not ideal - so you might want to check this and take some actions to secure this directory if possible. I appreciate that this is probably a test deployment so it might not be a big deal, but it's always good to keep mindful of security :)
Edit #2
Okay YMMV with this, I am no .htaccess expert but you could deploy your symfony app to /www/symfony/ and rewrite the /test URI to show /symfony/web/ instead; e.g:
RewriteEngine On
# rewrite all `/test/*` uris to `symfony/web`
RewriteRule ^test(.*)$ symfony/web/$1 [L,QSA]
# direct access to /symfony dir is a 404
RewriteRule !^symfony/web/$1 - [R=404]
This should serve all applicable uri requests (to /test and /symfony/web itself) to Symfony, while restricting direct access to the symfony core files.
Haven't tested this, so how this will play with Symfony's own .htaccess is not something I can answer off the top of my head.