HSTTWO-2366 HSTTWO-2393 added unit tests that validate expected behavior for DocumentResource. Also split off the 'getBestLink' in DocumentResource for better unit testing. Also added an extra distinguisher in finding the best mount: When multiple mounts can serve as best link because of same number of types and equal depth of contentpath, then, the depth of the mount is also a factor to decide the best mount : The deeper the mount, the more specific it is considered to be