Test PBKDF2 iteration fallback

src/tests/test_kdf_iteration_fallback.py

@@ -0,0 +1,51 @@
+import bcrypt
+from pathlib import Path
+from tempfile import TemporaryDirectory
+
+from helpers import TEST_SEED, TEST_PASSWORD
+from utils.fingerprint import generate_fingerprint
+from utils.key_derivation import derive_index_key, derive_key_from_password
+from seedpass.core.encryption import EncryptionManager
+from seedpass.core.vault import Vault
+from seedpass.core.config_manager import ConfigManager
+from seedpass.core.manager import PasswordManager, EncryptionMode
+
+
+def test_kdf_iteration_fallback(monkeypatch):
+    with TemporaryDirectory() as td:
+        tmp = Path(td)
+        fp_name = generate_fingerprint(TEST_SEED)
+        fp_dir = tmp / fp_name
+        fp_dir.mkdir()
+
+        seed_key = derive_key_from_password(TEST_PASSWORD, fp_name, iterations=100_000)
+        EncryptionManager(seed_key, fp_dir).encrypt_parent_seed(TEST_SEED)
+
+        index_key = derive_index_key(TEST_SEED)
+        enc_mgr = EncryptionManager(index_key, fp_dir)
+        vault = Vault(enc_mgr, fp_dir)
+        cfg_mgr = ConfigManager(vault, fp_dir)
+        cfg = cfg_mgr.load_config(require_pin=False)
+        cfg["password_hash"] = bcrypt.hashpw(
+            TEST_PASSWORD.encode(), bcrypt.gensalt()
+        ).decode()
+        cfg["kdf_iterations"] = 100_000
+        cfg_mgr.save_config(cfg)
+
+        cfg["kdf_iterations"] = 50_000
+        cfg_mgr.save_config(cfg)
+
+        pm = PasswordManager.__new__(PasswordManager)
+        pm.encryption_mode = EncryptionMode.SEED_ONLY
+        pm.config_manager = cfg_mgr
+        pm.fingerprint_dir = fp_dir
+        pm.current_fingerprint = fp_name
+        pm.verify_password = lambda pw: True
+
+        monkeypatch.setattr(
+            "seedpass.core.manager.prompt_existing_password", lambda *_: TEST_PASSWORD
+        )
+
+        assert pm.setup_encryption_manager(fp_dir, exit_on_fail=False)
+        assert pm.parent_seed == TEST_SEED
+        assert cfg_mgr.get_kdf_iterations() == 100_000