Add tests for load_archive_metadata in _archive_helper.py

Co-authored-by: google-labs-jules[bot] <161369871+google-labs-jules[bot]@users.noreply.github.com>

Author: badMade

tests/test_archive_helper.py

@@ -0,0 +1,31 @@
+import json
+import unittest
+from unittest import mock
+
+from src._archive_helper import load_archive_metadata
+
+
+class TestArchiveHelper(unittest.TestCase):
+    @mock.patch("pathlib.Path.read_text")
+    def test_load_archive_metadata_success(
+        self, mock_read_text: mock.MagicMock
+    ) -> None:
+        mock_read_text.return_value = '{"foo": "bar"}'
+        result = load_archive_metadata("my_package")
+        self.assertEqual(result, {"foo": "bar"})
+
+    @mock.patch("pathlib.Path.read_text")
+    def test_load_archive_metadata_file_not_found(
+        self, mock_read_text: mock.MagicMock
+    ) -> None:
+        mock_read_text.side_effect = FileNotFoundError("No such file or directory")
+        with self.assertRaises(FileNotFoundError):
+            load_archive_metadata("my_package")
+
+    @mock.patch("pathlib.Path.read_text")
+    def test_load_archive_metadata_invalid_json(
+        self, mock_read_text: mock.MagicMock
+    ) -> None:
+        mock_read_text.return_value = '{"foo": '
+        with self.assertRaises(json.JSONDecodeError):
+            load_archive_metadata("my_package")