Always validate Backup before restoring (#5632)

* Validate Backup always before restoring

Since #5519 we check the encryption password early in restore case.
This has the side effect that we check the file existance early too.
However, in the non-encryption case, the file is not checked early.

This PR changes the behavior to always validate the backup file before
restoring, ensuring both encryption and non-encryption cases are
handled consistently.

In particular, the last case of test_restore_immediate_errors actually
validates that behavior. That test should actually have failed so far.
But it seems that because we validate the backup shortly after freeze
anyways, the exception still got raised early enough.

A simply `await asyncio.sleep(10)` right after the freeze makes the
test case fail. With this change, the test works consistently.

* Address pylint

* Fix backup_manager tests

* Drop warning message

tests/backups/test_backup.py

@@ -11,7 +11,7 @@ import pytest
 from supervisor.backups.backup import Backup
 from supervisor.backups.const import BackupType
 from supervisor.coresys import CoreSys
-from supervisor.exceptions import BackupFileNotFoundError
+from supervisor.exceptions import BackupFileNotFoundError, BackupInvalidError
 
 from tests.common import get_fixture_path
 
@@ -79,22 +79,21 @@ async def test_consolidate(
 
 @pytest.mark.asyncio
 @pytest.mark.parametrize(
-    "tarfile_side_effect, securetar_side_effect, expected_result, expect_exception",
+    "tarfile_side_effect, securetar_side_effect, expected_exception",
     [
-        (None, None, True, False),  # Successful validation
-        (FileNotFoundError, None, None, True),  # File not found
-        (None, tarfile.ReadError, False, False),  # Invalid password
+        (None, None, None),  # Successful validation
+        (FileNotFoundError, None, BackupFileNotFoundError),  # File not found
+        (None, tarfile.ReadError, BackupInvalidError),  # Invalid password
     ],
 )
-async def test_validate_password(
+async def test_validate_backup(
     coresys: CoreSys,
     tmp_path: Path,
     tarfile_side_effect,
     securetar_side_effect,
-    expected_result,
-    expect_exception,
+    expected_exception,
 ):
-    """Parameterized test for validate_password."""
+    """Parameterized test for validate_backup."""
     enc_tar = Path(copy(get_fixture_path("backup_example_enc.tar"), tmp_path))
     enc_backup = Backup(coresys, enc_tar, "test", None)
     await enc_backup.load()
@@ -120,9 +119,8 @@ async def test_validate_password(
             MagicMock(side_effect=securetar_side_effect),
         ),
     ):
-        if expect_exception:
-            with pytest.raises(BackupFileNotFoundError):
-                await enc_backup.validate_password(None)
+        if expected_exception:
+            with pytest.raises(expected_exception):
+                await enc_backup.validate_backup(None)
         else:
-            result = await enc_backup.validate_password(None)
-            assert result == expected_result
+            await enc_backup.validate_backup(None)