Fix pyright errors and coverage pragmas

- Add type annotations to memory object streams in tests
- Import SessionMessage for type annotations
- Add pragma: no cover to lines 556 and 571 specifically

Github-Issue:#1654

Author: felixweinberger

src/mcp/client/streamable_http.py

@@ -553,7 +553,7 @@ async def resume_stream(
                 timeout=httpx.Timeout(self.timeout, read=self.sse_read_timeout),
             ) as event_source:
                 event_source.response.raise_for_status()
-                logger.debug(f"Resumed SSE stream from event ID: {last_event_id}")
+                logger.debug(f"Resumed SSE stream from event ID: {last_event_id}")  # pragma: no cover
 
                 async for sse in event_source.aiter_sse():  # pragma: no cover
                     _is_complete, has_event_id = await self._handle_sse_event(
@@ -568,7 +568,7 @@ async def resume_stream(
 
         except httpx.HTTPStatusError as exc:
             if exc.response.status_code == 405:
-                logger.debug("Server does not support SSE resumption via GET")
+                logger.debug("Server does not support SSE resumption via GET")  # pragma: no cover
             else:
                 logger.warning(f"Failed to resume stream: {exc}")
         except Exception as exc:  # pragma: no cover

tests/shared/test_streamable_http.py

@@ -39,7 +39,7 @@
 from mcp.server.transport_security import TransportSecuritySettings
 from mcp.shared.context import RequestContext
 from mcp.shared.exceptions import McpError
-from mcp.shared.message import ClientMessageMetadata
+from mcp.shared.message import ClientMessageMetadata, SessionMessage
 from mcp.shared.session import RequestResponder
 from mcp.types import InitializeResult, TextContent, TextResourceContents, Tool
 from tests.test_helpers import wait_for_server
@@ -1768,8 +1768,10 @@ async def test_resume_stream_without_session_id():
     transport = StreamableHTTPTransport("http://localhost:8000")
     assert transport.session_id is None
 
-    # Create a dummy stream writer
-    read_stream_writer, read_stream_reader = anyio.create_memory_object_stream(0)
+    # Create a dummy stream writer with type annotation
+    read_stream_writer, read_stream_reader = anyio.create_memory_object_stream[
+        SessionMessage | Exception
+    ](0)
 
     async with httpx.AsyncClient() as client:
         # Should return early without making request
@@ -1804,7 +1806,9 @@ async def test_resume_stream_with_405_response(basic_server: None, basic_server_
             transport.session_id = get_session_id()
 
     # Now try to resume with the session - server might return 405
-    read_stream_writer, read_stream_reader = anyio.create_memory_object_stream(0)
+    read_stream_writer, read_stream_reader = anyio.create_memory_object_stream[
+        SessionMessage | Exception
+    ](0)
 
     async with httpx.AsyncClient() as client:
         # This should handle the 405 gracefully