worked on tests for cache class

tests/test_cache.py

 #script to test the cache for the rest client.
 
+import pytest
+from unittest import mock
+import datetime
 
 from toargridding.toar_rest_client import Cache
 from pathlib import Path
 
-
 def test_cache():
     myTestCache = Cache( cache_dir=Path("cache"), fn="testingOfCache")
     
@@ -14,6 +16,8 @@ def test_cache():
     assert "test key 1" in myTestCache 
     assert "test key 2" in myTestCache 
     assert myTestCache.get("test key 1") == "test content 1"
+    myTestCache.clearCache()
+    assert "test key 2" in myTestCache
     
     #edit creation date of key 2:
     with myTestCache.storage_dict() as storage: