added test exception on composite metadata tag longer than 256

rsocket/extensions/tagging.py

@@ -1,6 +1,7 @@
 import struct
 from typing import Union, List, Optional
 
+from rsocket.exceptions import RSocketError
 from rsocket.extensions.composite_metadata import CompositeMetadataItem
 from rsocket.frame_helpers import ensure_bytes
 
@@ -25,7 +26,7 @@ def _serialize_tags(self) -> bytes:
 
         for tag in list(map(ensure_bytes, self.tags)):
             if len(tag) > 256:
-                raise Exception('Tag length longer than 256 characters')
+                raise RSocketError('Tag length longer than 256 characters: "%s"' % tag)
 
             serialized += struct.pack('>b', len(tag))
             serialized += tag

tests/rsocket/test_composite_metadata.py

@@ -0,0 +1,14 @@
+import pytest
+
+from rsocket.exceptions import RSocketError
+from rsocket.extensions.composite_metadata import CompositeMetadata
+from rsocket.extensions.routing import RoutingMetadata
+
+
+def test_tag_composite_metadata_too_long():
+    routing = RoutingMetadata(tags=[('some data too long %s' % ''.join(['x'] * 256)).encode()])
+    composite_metadata = CompositeMetadata()
+    composite_metadata.items.append(routing)
+
+    with pytest.raises(RSocketError):
+        composite_metadata.serialize()

tests/rsocket/test_frame.py

@@ -240,7 +240,7 @@ async def test_request_channel_frame(connection, follows, complete):
     assert composite_metadata.serialize() == frame.metadata
 
 
-async def test_basic_composite_metadata_item():
+def test_basic_composite_metadata_item():
     data = build_frame(
 
         bits(1, 1, 'Well known metadata type'),