changed testing method in cache tests to avoid garbage when cache content is not ok
changed testing method in cache tests to avoid garbage when cache content is not ok

git-svn-id: b349400a064d1b7ba2fe2e12028965f19dc7fbaa@3093 ee427ae8-e902-0410-961c-c3ed070cd9f9

WIZARDISHUNGRY/symfony,tedconf/symfony-unofficial,jcoby/symfony,tedconf/symfony-unofficial,tedconf/symfony-unofficial,WIZARDISHUNGRY/symfony,WIZARDISHUNGRY/symfony,jcoby/symfony,jcoby/symfony