fix: registry test_case (#197)

Test cases for `is_model_stale` had freeze time set to fixed date. 
Now, when redis is fetching data that is older than 10 days (cause ttl
is set to 10 days), it automatically deletes this key and hence we were
seeing ModelKeyNotFound error.

Signed-off-by: s0nicboOm <i.kushalbatra@gmail.com>

tests/registry/test_redis_registry.py

@@ -1,4 +1,5 @@
 import unittest
+from datetime import datetime, timedelta
 from unittest.mock import Mock, patch
 
 import fakeredis
@@ -128,15 +129,17 @@ def test_load_model_with_version(self):
         self.assertEqual(data.extras["version"], version)
 
     def test_check_if_model_stale_true(self):
-        with freeze_time("2023-05-08 12:30:00"):
+        delta = datetime.today() - timedelta(days=5)
+        with freeze_time(delta):
             self.registry.save(skeys=self.skeys, dkeys=self.dkeys, artifact=self.pytorch_model)
         data = self.registry.load(skeys=self.skeys, dkeys=self.dkeys)
         self.assertTrue(self.registry.is_artifact_stale(data, 12))
 
     def test_check_if_model_stale_false(self):
-        with freeze_time("2023-05-08 12:30:00"):
+        delta = datetime.today()
+        with freeze_time(delta):
             self.registry.save(skeys=self.skeys, dkeys=self.dkeys, artifact=self.pytorch_model)
-        with freeze_time("2023-05-08 19:30:00"):
+        with freeze_time(delta + timedelta(hours=7)):
             data = self.registry.load(skeys=self.skeys, dkeys=self.dkeys)
             self.assertFalse(self.registry.is_artifact_stale(data, 8))