Fix banana pudding recipe model

pytest.ini

@@ -0,0 +1,2 @@
+[pytest]
+testpaths = src/tests

src/recipes/banana_pudding.py

@@ -1 +1,13 @@
-obj['code']
+"""Minimal banana pudding recipe model used by the test suite."""
+
+from __future__ import annotations
+
+
+class BananaPudding:
+    """Simple container for banana pudding ingredients."""
+
+    def __init__(self) -> None:
+        self.ingredients: list[dict[str, object]] = []
+
+    def add_ingredient(self, name: str, amount: object) -> None:
+        self.ingredients.append({"name": name, "amount": amount})

src/tests/conftest.py

@@ -0,0 +1,16 @@
+"""Test bootstrap for the src-based modules.
+
+Pytest runs from the repository root, so add ``src/`` to ``sys.path`` once for
+the test session instead of relying on an ad hoc environment variable.
+"""
+
+from __future__ import annotations
+
+import sys
+from pathlib import Path
+
+
+SRC_DIR = Path(__file__).resolve().parents[1]
+src_path = str(SRC_DIR)
+if src_path not in sys.path:
+    sys.path.insert(0, src_path)