test(backups): erase repos between tests

selfprivacy_api/backup/backuppers/none_backupper.py

@@ -25,7 +25,8 @@ class NoneBackupper(AbstractBackupper):
 
     def erase_repo(self) -> None:
         """Completely empties the remote"""
-        raise NotImplementedError
+        # this one is already empty
+        pass
 
     def restore_from_backup(self, snapshot_id: str, folders: List[str], verify=True):
         """Restore a target folder using a snapshot"""

tests/test_graphql/test_backup.py

@@ -66,7 +66,7 @@ def backups(tmpdir):
 
     Backups.init_repo()
     yield
-    Backups.forget_all_snapshots()
+    Backups.erase_repo()
 
 
 @pytest.fixture()