i'm working on smarter caching of test files, so that extracting and preparing will not be run if only the osrm-routed binary changed.

but it seems that relinking will change the bins even though no source code has changed. somehow linking must involve a timestamp or random number? after running 'rake' from the root folder, all the bins have new a new sha1sum, which makes it impossible to skip the extraction/preparing step.

running osrm-extract -v shows the same version string; the git revision is unchanged, and there's no data info. so it must be something else.