The Mercurial way seems to be to handle files and only files.
Metadata, like svn proprerties, indicating whether tests habve passed or not, in the Mercurial mindset lives only in files. See, for example:
http://stackoverflow.com/questions/4443712/is-there-a-mercurial-extension-like-svn-propset
I actually am okay by this. Keep stuff in files. However, I think there are issues wrt how a workspace should be assembled: more and more I think of a workspace as an overlay of metadata, in files, that transcends versions, and the actual versioned source code files.
I.e. if you have a file that describes all of the branches in a repo, and what they are used for, it rather defeats the purpose if, when you update the workspace to a branch, you lose other