Merge branch '478-backup-health-check-broken-due-to-missing-mathematical-knowledge' into 'master'

Resolve "Backup health check broken due to missing mathematical knowledge"

Closes #478

See merge request !658

CHANGELOG.rst

@@ -6,6 +6,14 @@ All notable changes to this project will be documented in this file.
 The format is based on `Keep a Changelog`_,
 and this project adheres to `Semantic Versioning`_.
 
+Unreleased
+----------
+
+Fixed
+~~~~~
+
+* Fix broken backup health check
+
 `2.0b1`_ - 2021-06-01
 ---------------------
 

aleksis/core/health_checks.py

@@ -38,9 +38,9 @@ class BaseBackupHealthCheck(BaseHealthCheckBackend):
             self.add_error(_("The backup folder doesn't exist."))
             return
         if backups:
-            last_backup = backups[-1]
-            last_backup_time = dbbackup_utils.filename_to_date(last_backup)
-            time_gone_since_backup = last_backup_time - datetime.now()
+            last_backup = backups[:1]
+            last_backup_time = dbbackup_utils.filename_to_date(last_backup[0])
+            time_gone_since_backup = datetime.now() - last_backup_time
 
             # Check if backup is older than configured time
             if time_gone_since_backup.seconds > self.configured_seconds: