use OVL (Open Verification Library) with Quartus II VHDL

You need to include the source files in your project. Quartus is pretty rubbish at library management so just keep with what you would usually write for modelsim, and quartus will just search all source files in the project for the relavent entity (it basically just ignores the library name you put - it almost treats every library as if it were the work library).