feat(backend): data loader handles test cases

backend/scripts/load_data.py

@@ -9,6 +9,7 @@ from typing import Any
 import yaml
 from sqlalchemy import select
 from sqlalchemy.ext.asyncio import AsyncSession
+from sqlalchemy.orm import selectinload
 
 # Add src to path for imports
 sys.path.insert(0, str(Path(__file__).parent.parent))
@@ -96,28 +97,41 @@ async def load_question(
         data: dict[str, Any] = yaml.safe_load(f)
 
     slug = data["slug"]
-    result = await session.execute(select(Question).where(Question.slug == slug))
+    result = await session.execute(
+        select(Question)
+        .where(Question.slug == slug)
+        .options(
+            selectinload(Question.explanation),
+            selectinload(Question.solutions),
+            selectinload(Question.categories),
+            selectinload(Question.patterns),
+        )
+    )
     existing = result.scalar_one_or_none()
 
     if existing:
         question = existing
         question.title = data["title"]
-        question.difficulty = Difficulty(data["difficulty"])
+        question.difficulty = Difficulty(data["difficulty"].lower())
         question.description = data["description"]
         question.constraints = data.get("constraints")
         question.examples = data.get("examples")
         question.leetcode_id = data.get("leetcode_id")
         question.leetcode_url = data.get("leetcode_url")
+        question.function_signature = data.get("function_signature")
+        question.test_cases = data.get("test_cases")
     else:
         question = Question(
             title=data["title"],
             slug=slug,
-            difficulty=Difficulty(data["difficulty"]),
+            difficulty=Difficulty(data["difficulty"].lower()),
             description=data["description"],
             constraints=data.get("constraints"),
             examples=data.get("examples"),
             leetcode_id=data.get("leetcode_id"),
             leetcode_url=data.get("leetcode_url"),
+            function_signature=data.get("function_signature"),
+            test_cases=data.get("test_cases"),
         )
         session.add(question)
 
@@ -136,7 +150,7 @@ async def load_question(
     # Handle explanation
     if "explanation" in data:
         exp_data = data["explanation"]
-        if question.explanation:
+        if existing and existing.explanation:
             explanation = question.explanation
             explanation.approach = exp_data["approach"]
             explanation.intuition = exp_data["intuition"]