tests: use AES-GCM key generation

src/tests/test_encryption_files.py

@@ -3,7 +3,8 @@ import sys
 from pathlib import Path
 from tempfile import TemporaryDirectory
 
-from cryptography.fernet import Fernet
+import os
+import base64
 
 sys.path.append(str(Path(__file__).resolve().parents[1]))
 
@@ -12,7 +13,7 @@ from password_manager.encryption import EncryptionManager
 
 def test_json_save_and_load_round_trip():
     with TemporaryDirectory() as tmpdir:
-        key = Fernet.generate_key()
+        key = base64.urlsafe_b64encode(os.urandom(32))
         manager = EncryptionManager(key, Path(tmpdir))
 
         data = {"hello": "world", "nums": [1, 2, 3]}
@@ -27,7 +28,7 @@ def test_json_save_and_load_round_trip():
 
 def test_encrypt_and_decrypt_file_binary_round_trip():
     with TemporaryDirectory() as tmpdir:
-        key = Fernet.generate_key()
+        key = base64.urlsafe_b64encode(os.urandom(32))
         manager = EncryptionManager(key, Path(tmpdir))
 
         payload = b"binary secret"