Add portable backup export/import

src/tests/test_portable_backup.py

@@ -0,0 +1,116 @@
+import json
+import base64
+from pathlib import Path
+from tempfile import TemporaryDirectory
+
+import pytest
+import sys
+
+sys.path.append(str(Path(__file__).resolve().parents[1]))
+
+from password_manager.encryption import EncryptionManager
+from password_manager.vault import Vault
+from password_manager.backup import BackupManager
+from password_manager.portable_backup import (
+    PortableMode,
+    export_backup,
+    import_backup,
+)
+from utils.key_derivation import derive_index_key, EncryptionMode
+
+
+SEED = "abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon about"
+PASSWORD = "passw0rd"
+
+
+def setup_vault(tmp: Path, mode: EncryptionMode = EncryptionMode.SEED_ONLY):
+    index_key = derive_index_key(SEED, PASSWORD, mode)
+    enc_mgr = EncryptionManager(index_key, tmp)
+    enc_mgr.encrypt_parent_seed(SEED)
+    vault = Vault(enc_mgr, tmp)
+    backup = BackupManager(tmp)
+    return vault, backup
+
+
+def test_round_trip_across_modes(monkeypatch):
+    for pmode in [
+        PortableMode.SEED_ONLY,
+        PortableMode.SEED_PLUS_PW,
+        PortableMode.PW_ONLY,
+    ]:
+        with TemporaryDirectory() as td:
+            tmp = Path(td)
+            vault, backup = setup_vault(tmp)
+            data = {"pw": 1}
+            vault.save_index(data)
+
+            monkeypatch.setattr(
+                "password_manager.portable_backup.prompt_existing_password",
+                lambda *_a, **_k: PASSWORD,
+            )
+
+            path = export_backup(vault, backup, pmode)
+            assert path.exists()
+
+            vault.save_index({"pw": 0})
+            import_backup(vault, backup, path)
+            assert vault.load_index() == data
+
+
+def test_corruption_detection(monkeypatch):
+    with TemporaryDirectory() as td:
+        tmp = Path(td)
+        vault, backup = setup_vault(tmp)
+        vault.save_index({"a": 1})
+
+        monkeypatch.setattr(
+            "password_manager.portable_backup.prompt_existing_password",
+            lambda *_a, **_k: PASSWORD,
+        )
+        path = export_backup(vault, backup, PortableMode.SEED_ONLY)
+
+        content = json.loads(path.read_text())
+        payload = base64.b64decode(content["payload"])
+        payload = b"x" + payload[1:]
+        content["payload"] = base64.b64encode(payload).decode()
+        path.write_text(json.dumps(content))
+
+        with pytest.raises(ValueError):
+            import_backup(vault, backup, path)
+
+
+def test_incorrect_credentials(monkeypatch):
+    with TemporaryDirectory() as td:
+        tmp = Path(td)
+        vault, backup = setup_vault(tmp)
+        vault.save_index({"a": 2})
+
+        monkeypatch.setattr(
+            "password_manager.portable_backup.prompt_existing_password",
+            lambda *_a, **_k: PASSWORD,
+        )
+        path = export_backup(vault, backup, PortableMode.SEED_PLUS_PW)
+
+        monkeypatch.setattr(
+            "password_manager.portable_backup.prompt_existing_password",
+            lambda *_a, **_k: "wrong",
+        )
+        with pytest.raises(Exception):
+            import_backup(vault, backup, path)
+
+
+def test_import_over_existing(monkeypatch):
+    with TemporaryDirectory() as td:
+        tmp = Path(td)
+        vault, backup = setup_vault(tmp)
+        vault.save_index({"v": 1})
+
+        monkeypatch.setattr(
+            "password_manager.portable_backup.prompt_existing_password",
+            lambda *_a, **_k: PASSWORD,
+        )
+        path = export_backup(vault, backup, PortableMode.SEED_ONLY)
+
+        vault.save_index({"v": 2})
+        import_backup(vault, backup, path)
+        assert vault.load_index() == {"v": 1}