Add comments as requested

tests/components/backup/conftest.py

@@ -80,7 +80,11 @@ def mock_create_backup() -> Generator[AsyncMock]:
 
 @pytest.fixture(name="mock_ha_version")
 def mock_ha_version_fixture(hass: HomeAssistant) -> Generator[None]:
-    """Mock HA version."""
+    """Mock HA version.
+
+    The HA version is included in backup metadata. We mock it for the benefit
+    of tests that check the exact content of the metadata.
+    """
 
     with patch("homeassistant.components.backup.manager.HAVERSION", "2025.1.0"):
         yield

tests/components/backup/test_util.py

@@ -133,14 +133,19 @@ def test_read_backup(backup_json_content: bytes, expected_backup: AgentBackup) -
 @pytest.mark.parametrize(
     ("backup", "password", "validation_result"),
     [
+        # Backup not protected, no password provided -> validation passes
         (Path("backup_v2_compressed.tar"), None, True),
         (Path("backup_v2_uncompressed.tar"), None, True),
+        # Backup not protected, password provided -> validation fails
         (Path("backup_v2_compressed.tar"), "hunter2", False),
         (Path("backup_v2_uncompressed.tar"), "hunter2", False),
+        # Backup protected, correct password provided -> validation passes
         (Path("backup_v2_compressed_protected.tar"), "hunter2", True),
         (Path("backup_v2_uncompressed_protected.tar"), "hunter2", True),
+        # Backup protected, no password provided -> validation fails
         (Path("backup_v2_compressed_protected.tar"), None, False),
         (Path("backup_v2_uncompressed_protected.tar"), None, False),
+        # Backup protected, wrong password provided -> validation fails
         (Path("backup_v2_compressed_protected.tar"), "wrong_password", False),
         (Path("backup_v2_uncompressed_protected.tar"), "wrong_password", False),
     ],