test(e2e): report batch cleanup leftovers as a plain UserWarning (#43405)

The leftover warning used a class defined in a test-directory module. The xdist controller cannot import it, so an uncaught leftover warning crashed the whole e2e run. Same change as #43391 on rc/1.103.0

tests/e2e/batches/COVERAGE.md

@@ -134,7 +134,7 @@ reporting failures as test errors. Already deleted files and batches that are
 terminal are safe to clean up again. Managed batch cancellation polls for up to two minutes
 before input deletion. A managed batch still `cancelling` after that is left for the provider to
 finish, and its input file is left in place because LiteLLM refuses to delete a file a non-terminal
-batch references. Both are reported as `BatchCleanupLeftover` warnings naming their ids rather than
+batch references. Both are reported as `UserWarning`s naming their ids rather than
 failing the test. Any other status or error still fails
 Accepted cancellation may still report validating or in_progress while the provider
 updates its state. Raw and model-encoded batches are polled until cancelling or

tests/e2e/batches/batch_cleanup.py

@@ -28,10 +28,6 @@ class BatchCleanupClient(Protocol):
     def cancel_batch(self, batch_id: str, *, key: str, provider: str | None = None) -> Result[BatchObject]: ...
 
 
-class BatchCleanupLeftover(UserWarning):
-    pass
-
-
 def cleanup_result[R: BaseModel](
     action: Callable[[], Result[R]], *, wait: Callable[[float], None] = sleep
 ) -> Result[R]:
@@ -68,7 +64,7 @@ def cleanup_file(client: BatchCleanupClient, file_id: str, *, key: str, provider
     if isinstance(result, UnknownApiError) and result.status_code == 400 and FILE_IN_USE_REFUSAL in result.body:
         warnings.warn(
             f"Left file {file_id} in place: LiteLLM refused to delete it while a batch still references it",
-            BatchCleanupLeftover,
+            UserWarning,
             stacklevel=2,
         )
         return
@@ -140,7 +136,7 @@ def cleanup_batch(
             )
             warnings.warn(
                 f"Left batch {batch_id} cancelling after {BATCH_CANCEL_TIMEOUT_SECONDS}s for the provider to finish",
-                BatchCleanupLeftover,
+                UserWarning,
                 stacklevel=2,
             )
             return

tests/e2e/batches/test_batch_cleanup.py

@@ -7,7 +7,6 @@ import pytest
 from batch_cleanup import (
     BATCH_CANCEL_TIMEOUT_SECONDS,
     CLEANUP_DELAYS,
-    BatchCleanupLeftover,
     cleanup_batch,
     cleanup_file,
     cleanup_result,
@@ -141,7 +140,7 @@ class TestFileCleanup:
             calls=ExpectedCalls((f"delete None {MANAGED_FILE_ID}",)),
             files=(UnknownApiError(status_code=400, body=IN_USE_REFUSAL),),
         )
-        with pytest.warns(BatchCleanupLeftover, match=MANAGED_FILE_ID):
+        with pytest.warns(UserWarning, match=MANAGED_FILE_ID):
             cleanup_file(client, MANAGED_FILE_ID, key="test-key")
         client.calls.assert_done()
 
@@ -241,7 +240,7 @@ class TestBatchCancellation:
         key: Final = manager.key()
         manager.defer(lambda: cleanup_file(client, MANAGED_FILE_ID, key=key))
         manager.defer(lambda: cleanup_batch(client, MANAGED_BATCH_ID, key=key, clock=ticks))
-        with pytest.warns(BatchCleanupLeftover) as leftovers:
+        with pytest.warns(UserWarning, match="^Left ") as leftovers:
             manager.teardown()
         client.calls.assert_done()
         messages: Final = tuple(str(warning.message) for warning in leftovers)