Fix broad exception handling and future.result() call

- Call future.result() instead of bare property access in test (#596)
- Catch (ValueError, TypeError) instead of broad Exception in
  response model serialization (#597)
- Catch WebSocketDisconnect instead of broad Exception in
  websocket chat example (#598)

Closes #596, closes #597, closes #598

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

examples/websocket_chat.py

@@ -1,5 +1,7 @@
 # WebSocket chat room example.
 # https://responder.kennethreitz.org/tutorial-websockets.html
+from starlette.websockets import WebSocketDisconnect
+
 import responder
 
 api = responder.API()
@@ -47,7 +49,7 @@ async def chat(ws):
             message = await ws.receive_text()
             for client in connected:
                 await client.send_text(message)
-    except Exception:  # noqa: S110
+    except WebSocketDisconnect:
         pass
     finally:
         connected.discard(ws)

responder/routes.py

@@ -192,7 +192,7 @@ class Route(BaseRoute):
             try:
                 validated = resp_model(**response.media)
                 response.media = validated.model_dump()
-            except Exception:  # noqa: S110
+            except (ValueError, TypeError):
                 pass  # Don't break the response if serialization fails
 
         # Run after-request hooks

tests/test_coverage.py

@@ -78,7 +78,10 @@ def test_background_task_exception(capsys):
         raise ValueError("task failed")
 
     future = failing_task()
-    future.result  # wait for completion  # noqa: B018
+    try:
+        future.result()  # wait for completion
+    except ValueError:
+        pass
     time.sleep(0.2)  # let the done callback fire
 
     captured = capsys.readouterr()