Add tests for label repository (#5)

todo/tests/unit/repositories/test_label_repository.py

@@ -0,0 +1,42 @@
+from unittest import TestCase
+from unittest.mock import patch, MagicMock
+from pymongo.collection import Collection
+from todo.models.label import LabelModel
+from todo.repositories.label_repository import LabelRepository
+from todo.tests.fixtures.label import label_db_data
+
+
+class LabelRepositoryTests(TestCase):
+    def setUp(self):
+        self.label_ids = [label_data["_id"] for label_data in label_db_data]
+        self.label_data = label_db_data
+
+        self.patcher_get_collection = patch("todo.repositories.label_repository.LabelRepository.get_collection")
+        self.mock_get_collection = self.patcher_get_collection.start()
+        self.mock_collection = MagicMock(spec=Collection)
+        self.mock_get_collection.return_value = self.mock_collection
+
+    def tearDown(self):
+        self.patcher_get_collection.stop()
+
+    def test_list_by_ids_returns_label_models(self):
+        self.mock_collection.find.return_value = self.label_data
+
+        result = LabelRepository.list_by_ids(self.label_ids)
+
+        self.assertEqual(len(result), len(self.label_data))
+        self.assertTrue(all(isinstance(label, LabelModel) for label in result))
+
+    def test_list_by_ids_returns_empty_list_if_not_found(self):
+        self.mock_collection.find.return_value = []
+
+        result = LabelRepository.list_by_ids([self.label_ids[0]])
+
+        self.assertEqual(result, [])
+
+    def test_list_by_ids_skips_db_call_for_empty_input(self):
+        result = LabelRepository.list_by_ids([])
+
+        self.assertEqual(result, [])
+        self.mock_get_collection.assert_not_called()
+        self.mock_collection.assert_not_called()