Add functional and unit testing

[aaime]

GeoServer managed to stay long time without unit tests because it had the CITE tests to cover his back somehow, but GWC has nothing, meaning there is nothing preventing regressions and bug to creep in.
I'd say adding some form of testing (functional at least) should be top priority, before adding new features or doing refactorings on the code

[arneke]

Note that there were at least 7 unit tests for the grid and metatile functions, which create the least obvious errors.

I have created standard configurations (still need to make /tmp and %TEMP% more flexible) that let users easily inspect EPSG:900913 and EPSG:4326 if they can connect to sigma.openplans.org. But that's not very automated, do you have any particular tests in mind?

Fake a WMS and see how it comes out? Not sure how to compare the images reliably.