Optimize imports in test classes

tests/test_hierarchy.py

@@ -1,9 +1,12 @@
 import json
 import unittest
+from io import StringIO
+from pathlib import Path
+from unittest.mock import PropertyMock, patch
 
 from hypothesis import given
-from hypothesis.strategies import booleans, characters, iterables, one_of, none, text
-from pathlib import Path
+from hypothesis.strategies import characters, one_of, lists, text
+
 from rbackup.struct.hierarchy import Hierarchy
 
 # ========== Constants ==========