Use relative path in test

This is required to fix the test for https://github.com/kohana/kohana/pull/41.
> And it's already in kohana/kohana

Hmmm... You got me with this one.

There is a way to put Netbeans metadata into a separate directory, but it gives this warning:

> Warning: If Sources folder is not underneath or the same as NetBeans metadata directory, there could be problems with versioning of the project. The same applies if these folders are located on different hard drives.

Alright, I will merge.