fix: update mcp test mocks for SDK streamable transport#2664
Merged
Conversation
The newPlainJSONTestServer helper and TestConnection_SendRequest were not handling the SDK streamable transport protocol correctly: - newPlainJSONTestServer: add notifications/initialized handler (SDK sends this after successful initialize) - TestConnection_SendRequest: echo back request ID instead of hardcoding 1 (SDK assigns sequential IDs) Without these fixes, the SDK transport hangs waiting for a matching response ID during the initialize handshake. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Contributor
There was a problem hiding this comment.
Pull request overview
Updates MCP test mocks to align with the SDK’s Streamable HTTP transport handshake so internal/mcp tests don’t hang after transport selection changes (per #2608).
Changes:
- Teach
newPlainJSONTestServerto acknowledgenotifications/initializedwith202 Accepted. - Update
TestConnection_SendRequestmock handler to echo the incoming JSON-RPCidinstead of hardcoding1.
Reviewed changes
Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.
| File | Description |
|---|---|
| internal/mcp/sdk_method_dispatch_test.go | Adds a notifications/initialized acknowledgement to the plain JSON test server handshake. |
| internal/mcp/connection_stderr_test.go | Makes the mock response correlate with the request by echoing the JSON-RPC id. |
💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.
Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
This was referenced Mar 27, 2026
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
Fixes hanging
TestConnection_SendRequestininternal/mcpcaused by SDK streamable transport changes from #2608.Root cause: After #2608 removed the headers shortcut,
NewHTTPConnectionalways tries SDK streamable transport first. Two mock server issues caused hangs:newPlainJSONTestServerdidn't handlenotifications/initialized(SDK sends this afterinitialize)TestConnection_SendRequesthardcoded"id": 1— SDK assigns sequential IDs, so the response never matched theAwaitcallFix:
notifications/initializedhandler (202 Accepted) tonewPlainJSONTestServerreq["id"]instead of hardcoding1in the test handler