Fix dataframe_snapshot test on Windows
Fix dataframe_snapshot test on Windows

On Windows, one cannot delete a file while used by a process, so use different file names and make sure they are deleted beforehand

olifre/root,karies/root,root-mirror/root,root-mirror/root,root-mirror/root,karies/root,olifre/root,olifre/root,root-mirror/root,root-mirror/root,root-mirror/root,olifre/root,olifre/root,olifre/root,karies/root,olifre/root,root-mirror/root,olifre/root,karies/root,karies/root,root-mirror/root,root-mirror/root,karies/root,olifre/root,olifre/root,karies/root,olifre/root,root-mirror/root,root-mirror/root,karies/root,karies/root,karies/root,karies/root