id	summary	reporter	owner	description	type	status	priority	milestone	component	version	resolution	keywords	cc
13999	New MapCSS test that uses reference images	michael2402	team	"When debugging MapCSS is often found the need to create custom styles to track down issues.

This is quite annoying and I thought that it could be automated.

I wrote a test that uses sample OSM files and styles and renders them to small (256 x 256 px) images. Those images are then compared to a reference image. If the images differ, the rendered result is stored for the user to inspect.

This works as a good unit test for the renderer classes - we can detect changes and see the impact of changes visually. If we change the renderer in a good way we need to re-create the reference files.

If the team is fine with it, I would like to write some more tests and commit it.

While I was on it, I found the first potential bug (`ws.lowerIndex < offset` in `StyledMapRenderer` does not make sense)"	enhancement	closed	normal	17.04	Unit tests		fixed	mapcss	Klumbumbus