test(celery): Test that Celery queue only set for default exchange

This test checks that `messaging.destination.name` is only set for the default exchange. Other exchanges should not set this value, since the routing key may be different from the queue name.

tests/integrations/celery/test_celery.py

@@ -620,7 +620,7 @@ def example_task():
 
 @pytest.mark.parametrize("routing_key", ("celery", "custom"))
 @mock.patch("celery.app.task.Task.request")
-def test_messaging_destination_name(
+def test_messaging_destination_name_default_exchange(
     mock_request, routing_key, init_celery, capture_events
 ):
     celery_app = init_celery(enable_tracing=True)
@@ -635,3 +635,27 @@ def task(): ...
     (event,) = events
     (span,) = event["spans"]
     assert span["data"]["messaging.destination.name"] == routing_key
+
+
+@mock.patch("celery.app.task.Task.request")
+def test_messaging_destination_name_nondefault_exchange(
+    mock_request, init_celery, capture_events
+):
+    """
+    Currently, we only capture the routing key as the messaging.destination.name when
+    we are using the default exchange (""). This is because the default exchange ensures
+    that the routing key is the queue name. Other exchanges may not guarantee this
+    behavior.
+    """
+    celery_app = init_celery(enable_tracing=True)
+    events = capture_events()
+    mock_request.delivery_info = {"routing_key": "celery", "exchange": "custom"}
+
+    @celery_app.task()
+    def task(): ...
+
+    task.apply_async()
+
+    (event,) = events
+    (span,) = event["spans"]
+    assert "messaging.destination.name" not in span["data"]