Merge remote-tracking branch 'origin/1.0-dev' into ishymko/history-length

Author: ishymko

src/a2a/server/request_handlers/default_request_handler.py

@@ -552,11 +552,15 @@ async def on_subscribe_to_task(
 
         if task.status.state in TERMINAL_TASK_STATES:
             raise ServerError(
-                error=InvalidParamsError(
+                error=UnsupportedOperationError(
                     message=f'Task {task.id} is in terminal state: {task.status.state}'
                 )
             )
 
+        # The operation MUST return a Task object as the first event in the stream
+        # https://a2a-protocol.org/latest/specification/#316-subscribe-to-task
+        yield task
+
         task_manager = TaskManager(
             task_id=task.id,
             context_id=task.context_id,

tests/server/request_handlers/test_jsonrpc_handler.py

@@ -703,7 +703,9 @@ async def streaming_coro():
             collected_events: list[Any] = []
             async for event in response:
                 collected_events.append(event)
-            assert len(collected_events) == len(events)
+            assert (
+                len(collected_events) == len(events) + 1
+            )  # First event is task itself
             assert mock_task.history is not None and len(mock_task.history) == 0
 
     async def test_on_subscribe_no_existing_task_error(self) -> None:

tests/utils/test_task.py

@@ -5,7 +5,15 @@
 
 import pytest
 
-from a2a.types.a2a_pb2 import Artifact, Message, Part, Role, TaskState, GetTaskRequest, SendMessageConfiguration
+from a2a.types.a2a_pb2 import (
+    Artifact,
+    Message,
+    Part,
+    Role,
+    TaskState,
+    GetTaskRequest,
+    SendMessageConfiguration,
+)
 from a2a.utils.task import (
     apply_history_length,
     completed_task,
@@ -214,51 +222,54 @@ def test_decode_page_token_fails(self):
         )
 
 
-if __name__ == '__main__':
-    unittest.main()
-
-
-
 class TestApplyHistoryLength(unittest.TestCase):
     def setUp(self):
-        # Create a task with some history
         self.history = [
-            Message(message_id=str(i), role=Role.ROLE_USER, parts=[Part(text=f'msg {i}')])
+            Message(
+                message_id=str(i),
+                role=Role.ROLE_USER,
+                parts=[Part(text=f'msg {i}')],
+            )
             for i in range(5)
         ]
         artifacts = [Artifact(artifact_id='a1', parts=[Part(text='a')])]
         self.task = completed_task(
             task_id='t1',
             context_id='c1',
             artifacts=artifacts,
-            history=self.history
+            history=self.history,
         )
 
     def test_none_config_returns_full_history(self):
-        # Test None (no limit) - config is None
         result = apply_history_length(self.task, None)
         self.assertEqual(len(result.history), 5)
         self.assertEqual(result.history, self.history)
 
     def test_unset_history_length_returns_full_history(self):
-        # Test unset (HasField returns False)
-        # Using GetTaskRequest as it has history_length field
         result = apply_history_length(self.task, GetTaskRequest())
         self.assertEqual(len(result.history), 5)
         self.assertEqual(result.history, self.history)
 
     def test_positive_history_length_truncates(self):
-        # Test > 0 (partial)
-        result = apply_history_length(self.task, GetTaskRequest(history_length=2))
+        result = apply_history_length(
+            self.task, GetTaskRequest(history_length=2)
+        )
         self.assertEqual(len(result.history), 2)
         self.assertEqual(result.history, self.history[-2:])
 
     def test_large_history_length_returns_full_history(self):
-        result = apply_history_length(self.task, GetTaskRequest(history_length=10))
+        result = apply_history_length(
+            self.task, GetTaskRequest(history_length=10)
+        )
         self.assertEqual(len(result.history), 5)
         self.assertEqual(result.history, self.history)
 
     def test_zero_history_length_returns_empty_history(self):
-        result = apply_history_length(self.task, SendMessageConfiguration(history_length=0))
+        result = apply_history_length(
+            self.task, SendMessageConfiguration(history_length=0)
+        )
         self.assertEqual(len(result.history), 0)
 
+
+if __name__ == '__main__':
+    unittest.main()