docs: catch startup deprecated warning

docs_src/app_testing/tutorial003.py

@@ -1,3 +1,4 @@
+import warnings
 from fastapi import FastAPI
 from fastapi.testclient import TestClient
 
@@ -5,11 +6,14 @@ app = FastAPI()
 
 items = {}
 
+# startup event and shutdown event are deprecated, you should use lifespan instead
+with warnings.catch_warnings():
+    warnings.simplefilter("ignore", DeprecationWarning)
 
-@app.on_event("startup")
+    @app.on_event("startup")
-async def startup_event():
+    async def startup_event():
-    items["foo"] = {"name": "Fighters"}
+        items["foo"] = {"name": "Fighters"}
-    items["bar"] = {"name": "Tenders"}
+        items["bar"] = {"name": "Tenders"}
 
 
 @app.get("/items/{item_id}")