test(backups): test last backup date retrieval

selfprivacy_api/backup/__init__.py

@@ -58,6 +58,7 @@ class Backups:
 
     @staticmethod
     def get_last_backed_up(service: Service) -> Optional[datetime]:
+        """Get a timezone-aware time of the last backup of a service"""
         return Backups._get_last_backup_time_redis(service.get_id())
 
     @staticmethod
@@ -66,7 +67,7 @@ class Backups:
         if not redis.exists(key):
             return None
 
-        snapshot = hash_as_model(redis, key)
+        snapshot = hash_as_model(redis, key, Snapshot)
         return snapshot.created_at
 
     @staticmethod

tests/test_graphql/test_backup.py

@@ -3,6 +3,7 @@ import os.path as path
 from os import makedirs
 from os import remove
 from os import listdir
+from datetime import datetime, timedelta, timezone
 
 from selfprivacy_api.services.test_service import DummyService
 
@@ -113,8 +114,15 @@ def test_backup_simple_file(raw_dummy_service, file_backup):
 
 
 def test_backup_service(dummy_service, backups):
+    assert Backups.get_last_backed_up(dummy_service) is None
     Backups.back_up(dummy_service)
 
+    now = datetime.now(timezone.utc)
+    date = Backups.get_last_backed_up(dummy_service)
+    assert date is not None
+    assert now > date
+    assert now - date < timedelta(minutes=1)
+
 
 def test_no_repo(memory_backup):
     with pytest.raises(ValueError):