[Misc] Add __str__ for RequestStatus (#19780)

Signed-off-by: Linkun Chen <github@lkchen.net>

tests/v1/test_request.py

+# SPDX-License-Identifier: Apache-2.0
+from vllm.v1.request import RequestStatus
+
+
+def test_request_status_fmt_str():
+    """Test that the string representation of RequestStatus is correct."""
+    assert f"{RequestStatus.WAITING}" == "WAITING"
+    assert f"{RequestStatus.WAITING_FOR_FSM}" == "WAITING_FOR_FSM"
+    assert f"{RequestStatus.WAITING_FOR_REMOTE_KVS}" == "WAITING_FOR_REMOTE_KVS"
+    assert f"{RequestStatus.RUNNING}" == "RUNNING"
+    assert f"{RequestStatus.PREEMPTED}" == "PREEMPTED"
+    assert f"{RequestStatus.FINISHED_STOPPED}" == "FINISHED_STOPPED"
+    assert f"{RequestStatus.FINISHED_LENGTH_CAPPED}" == "FINISHED_LENGTH_CAPPED"
+    assert f"{RequestStatus.FINISHED_ABORTED}" == "FINISHED_ABORTED"
+    assert f"{RequestStatus.FINISHED_IGNORED}" == "FINISHED_IGNORED"

vllm/v1/request.py

@@ -171,6 +171,9 @@ class RequestStatus(enum.IntEnum):
     FINISHED_ABORTED = enum.auto()
     FINISHED_IGNORED = enum.auto()
 
+    def __str__(self):
+        return self.name
+
     @staticmethod
     def is_finished(status: "RequestStatus") -> bool:
         return status > RequestStatus.PREEMPTED