anchor.diff:  groups() ->
       [{new_leases, [], [new_lease
                         ,new_lease_busy
  -                      ,new_lease_expired]}
  +                      ,new_lease_expired
  +                      ,new_lease_conflict]}
       ,{end_leases, [], [remove_lease_existing
                         ,remove_lease_nonexisting
                         ,clear_leases]}
  
positive.code:     Secret = <<"secret">>,
      ok = cvmfs_lease:request_lease(U, P, Public, Secret),
      {error, invalid_lease} = cvmfs_lease:get_lease_path(<<"invalid_user">>).
  
  
negative.code:     Public = <<"public">>,
      Secret = <<"secret">>,
      ok = cvmfs_lease:request_lease(U, P, Public, Secret),
      [{lease, {P, <<>>}, U, Public, Secret, _}] = cvmfs_lease:get_leases(),
      ok = cvmfs_lease:clear_leases(),
      [] = cvmfs_lease:get_leases().
  
  