Fix broken tests

Author: mikeas1

src/a2a/auth/user.py

@@ -6,13 +6,13 @@
 class User(ABC):
     """A representation of an authenticated user."""
 
-    @abstractmethod
     @property
+    @abstractmethod
     def is_authenticated(self) -> bool:
         """Returns whether the current user is authenticated."""
 
-    @abstractmethod
     @property
+    @abstractmethod
     def user_name(self) -> str:
         """Returns the user name of the current user."""
 

src/a2a/server/apps/starlette_app.py

@@ -15,6 +15,7 @@
 from starlette.responses import JSONResponse, Response
 from starlette.routing import Route
 
+from a2a.auth.user import UnauthenticatedUser
 from a2a.auth.user import User as A2AUser
 from a2a.server.context import ServerCallContext
 from a2a.server.request_handlers.jsonrpc_handler import JSONRPCHandler
@@ -60,7 +61,7 @@ class DefaultCallContextBuilder(CallContextBuilder):
     """A default implementation of CallContextBuilder."""
 
     def build(self, request: Request) -> ServerCallContext:
-        user = None
+        user = UnauthenticatedUser()
         state = {}
         with contextlib.suppress(Exception):
             user = request.user

src/a2a/server/context.py

@@ -3,7 +3,7 @@
 import collections.abc
 import typing
 
-from pydantic import BaseModel, Field
+from pydantic import BaseModel, ConfigDict, Field
 
 from a2a.auth.user import UnauthenticatedUser, User
 
@@ -17,5 +17,7 @@ class ServerCallContext(BaseModel):
     This class allows storing arbitrary user data in the state attribute.
     """
 
+    model_config = ConfigDict(arbitrary_types_allowed=True)
+
     state: State = Field(default={})
     user: User = Field(default=UnauthenticatedUser())