feat: implement CI workflow, enhance file validation, and add test cases

- Introduced a CI workflow for automated testing of backend and frontend components.
- Added pytest configuration for backend tests and Vitest configuration for frontend tests.
- Enhanced file validation logic in the backend to improve error handling and reporting.
- Created comprehensive test cases for various validation scenarios, including edge cases and incorrect formats.
- Updated requirements to include necessary testing libraries and tools.

tests/backend/conftest.py

@@ -0,0 +1,46 @@
+import os
+import sys
+import pytest
+import pytest_asyncio
+import httpx
+
+sys.path.insert(0, os.path.join(os.path.dirname(__file__), '..', '..', 'backend'))
+import main
+
+
+@pytest_asyncio.fixture
+async def client():
+    transport = httpx.ASGITransport(app=main.app)
+    async with httpx.AsyncClient(transport=transport, base_url="http://testserver") as c:
+        yield c
+
+
+@pytest_asyncio.fixture(autouse=True)
+async def mock_db_services(monkeypatch):
+    """Mock database services to avoid requiring MongoDB"""
+    
+    # Mock database connection functions
+    async def mock_connect_to_mongo():
+        pass
+    
+    async def mock_close_mongo_connection():
+        pass
+    
+    monkeypatch.setattr(main, 'connect_to_mongo', mock_connect_to_mongo)
+    monkeypatch.setattr(main, 'close_mongo_connection', mock_close_mongo_connection)
+    
+    # Mock database service
+    class MockDatabaseService:
+        async def get_all_forms(self):
+            return []
+        
+        async def get_form_by_id(self, form_id: str):
+            return None  # Simulate form not found
+        
+        async def get_questions_by_form_id(self, form_id: str):
+            return []
+        
+        async def get_options_by_form_id(self, form_id: str):
+            return []
+    
+    monkeypatch.setattr(main, 'db_service', MockDatabaseService())