From 123bca1b9199d5c097da319e0e1e3fd3b789acbd Mon Sep 17 00:00:00 2001
From: Aya Hassan <ayahassan2877@gmail.com>
Date: Sun, 17 May 2026 19:19:29 +0200
Subject: [PATCH] Add S13

---
 .../test_send_errors_and_concurrency.py       | 81 +++++++++++++++++++
 1 file changed, 81 insertions(+)

diff --git a/tests/wrappers_tests/test_send_errors_and_concurrency.py b/tests/wrappers_tests/test_send_errors_and_concurrency.py
index eaa895a60..411db5b07 100644
--- a/tests/wrappers_tests/test_send_errors_and_concurrency.py
+++ b/tests/wrappers_tests/test_send_errors_and_concurrency.py
@@ -1,3 +1,4 @@
+import base64
 from concurrent.futures import ThreadPoolExecutor
 
 import pytest
@@ -13,6 +14,7 @@ from src.node.wrapper_helpers import (
     assert_event_invariants,
     create_message_bindings,
     get_node_multiaddr,
+    wait_for_connected,
     wait_for_propagated,
     wait_for_sent,
     wait_for_error,
@@ -30,6 +32,11 @@ CACHE_EXPIRY_SLACK_S = 10.0
 ERROR_AFTER_CACHE_EXPIRY_TIMEOUT_S = MAX_TIME_IN_CACHE_S + CACHE_EXPIRY_SLACK_S
 RETRY_WINDOW_EXPIRED_MSG = "Unable to send within retry time window"
 
+# Payload above DefaultMaxWakuMessageSize (150KiB), so the relay publish
+# rejects it instead of failing with NO_PEERS_TO_RELAY.
+OVERSIZED_PAYLOAD_BYTES = 200 * 1024
+ERROR_TIMEOUT_S = 30.0
+
 # S30: concurrent sends on the same content topic during initial auto-subscribe.
 S30_CONCURRENT_SENDS = 5
 S30_CONTENT_TOPIC = "/test/1/s30-concurrent/proto"
@@ -160,6 +167,80 @@ class TestS21ErrorWhenRetryWindowExpires(StepsCommon):
             assert_event_invariants(sender_collector, request_id)
 
 
+class TestS13RelayHardFailureWithoutFallback(StepsCommon):
+    """
+    S13: relay path is reachable (a relay peer is connected, so the publish
+    gets past NO_PEERS_TO_RELAY), but the relay publish fails for another
+    reason. An oversized payload is used so the relay processor rejects the
+    message immediately. No lightpush fallback is configured.
+      - Expected: Ok(RequestId), then a message_error event.
+    """
+
+    def test_s13_relay_hard_failure_without_fallback(self, node_config):
+        sender_collector = EventCollector()
+
+        node_config.update(
+            {
+                "relay": True,
+                "store": False,
+                "lightpush": False,
+                "filter": False,
+                "discv5Discovery": False,
+                "numShardsInNetwork": 1,
+            }
+        )
+
+        sender_result = WrapperManager.create_and_start(
+            config=node_config,
+            event_cb=sender_collector.event_callback,
+        )
+        assert sender_result.is_ok(), f"Failed to start sender: {sender_result.err()}"
+
+        with sender_result.ok_value as sender_node:
+            relay_config = {
+                **node_config,
+                "staticnodes": [get_node_multiaddr(sender_node)],
+                "portsShift": 1,
+            }
+
+            relay_result = WrapperManager.create_and_start(config=relay_config)
+            assert relay_result.is_ok(), f"Failed to start relay peer: {relay_result.err()}"
+
+            with relay_result.ok_value:
+                # A connected relay peer means the publish gets past
+                # NO_PEERS_TO_RELAY and actually reaches the relay processor.
+                assert wait_for_connected(sender_collector) is not None, (
+                    f"Sender did not reach Connected/PartiallyConnected. " f"Collected events: {sender_collector.events}"
+                )
+
+                oversized_payload = base64.b64encode(b"x" * OVERSIZED_PAYLOAD_BYTES).decode()
+                message = create_message_bindings(
+                    payload=oversized_payload,
+                    contentTopic="/test/1/s13-relay-hard-failure/proto",
+                )
+
+                send_result = sender_node.send_message(message=message)
+                assert send_result.is_ok(), f"send() must return Ok(RequestId), got: {send_result.err()}"
+
+                request_id = send_result.ok_value
+                assert request_id, "send() returned an empty RequestId"
+
+                error_event = wait_for_error(
+                    collector=sender_collector,
+                    request_id=request_id,
+                    timeout_s=ERROR_TIMEOUT_S,
+                )
+                assert error_event is not None, (
+                    f"No message_error event within {ERROR_TIMEOUT_S}s from the " f"relay processor. Collected events: {sender_collector.events}"
+                )
+                assert error_event["requestId"] == request_id
+
+                propagated = wait_for_propagated(sender_collector, request_id, timeout_s=0)
+                assert propagated is None, f"Unexpected message_propagated event for a failed relay publish: {propagated}"
+
+                assert_event_invariants(sender_collector, request_id)
+
+
 class TestS30ConcurrentSendsDuringAutoSubscribe(StepsCommon):
     """
     S30: concurrent sends on the same content topic during initial auto-subscribe.