fix(test): adapt MCP integration test to rmcp Streamable HTTP protocol

[im47cn]

Summary

The /api/mcp endpoint migrated from plain JSON-RPC to rmcp's StreamableHttpService, which wraps responses in SSE framing and requires a proper session handshake. The integration test (test_rust_backend_api) was still sending bare JSON-RPC POSTs without a session ID, causing panics when serde_json::from_slice hit non-JSON response bodies.

Changes

• Added mcp_request() helper that:
  • Sends proper initialize with protocolVersion, capabilities, and clientInfo
  • Captures mcp-session-id from the response header
  • Includes the session ID in subsequent requests
  • Sends notifications/initialized to complete the handshake
  • Parses both SSE (text/event-stream) and plain JSON responses
• Updated all 15 /api/mcp test calls (Tests 20–46) to use the protocol-aware helper

Test plan

• cargo test --test api_test passes (all 46 sub-tests)

Summary by CodeRabbit

• Tests
  • Expanded API integration coverage for both standard JSON and server-sent event responses.
  • Added MCP session handling throughout initialization and tool requests.
  • Added coverage for EventBus, orchestration, and extended MCP tools.
  • Improved verification of available MCP tools and session-based request behavior.

[coderabbitai]

📝 Walkthrough

Walkthrough

Changes

MCP API integration tests

Layer / File(s)	Summary
Response parsing and MCP request helpers apps/desktop/src-tauri/tests/api_test.rs	Shared helpers parse SSE-framed or plain JSON responses, set MCP headers, and extract session identifiers.
MCP handshake and session-scoped tools apps/desktop/src-tauri/tests/api_test.rs	Tests establish and complete an MCP session, reuse it across tool calls, and verify the expanded tool list.

Estimated code review effort: 4 (Complex) | ~45 minutes

Suggested reviewers: phodal

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly and accurately summarizes the main change: updating the MCP integration test for the Streamable HTTP protocol.
Description check	✅ Passed	The description covers the protocol migration, test changes, and validation, though the template's Notes section is missing.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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[coderabbitai]

🧹 Nitpick comments (1)

apps/desktop/src-tauri/tests/api_test.rs (1)

437-993: 📐 Maintainability & Code Quality | 🔵 Trivial | ⚡ Quick win

Consider extracting a small helper for repeated tools/call boilerplate.

Every migrated tool-call site repeats the same jsonrpc/id/method: "tools/call"/params: {name, arguments} envelope plus Some(&mcp_session_id). A thin wrapper would remove this duplication across all ~15 sites and make future protocol changes (e.g., another header) a one-line edit.

♻️ Example helper

async fn mcp_tool_call(
    app: &axum::Router,
    session_id: &str,
    id: i64,
    name: &str,
    arguments: Value,
) -> (StatusCode, Value) {
    let (status, _, body) = mcp_request(
        app,
        serde_json::json!({
            "jsonrpc": "2.0",
            "id": id,
            "method": "tools/call",
            "params": { "name": name, "arguments": arguments }
        }),
        Some(session_id),
    )
    .await;
    (status, body)
}

This is purely cosmetic/maintainability; functionally the migration is correct.

🤖 Prompt for AI Agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

In `@apps/desktop/src-tauri/tests/api_test.rs` around lines 437 - 993, The
repeated MCP tools/call request envelope should be centralized in a small
helper. Add an async mcp_tool_call helper near the existing mcp_request utility,
accepting app, session ID, request ID, tool name, and arguments, then update the
migrated tools/call sites to use it while preserving their existing assertions
and response handling.

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Nitpick comments:
In `@apps/desktop/src-tauri/tests/api_test.rs`:
- Around line 437-993: The repeated MCP tools/call request envelope should be
centralized in a small helper. Add an async mcp_tool_call helper near the
existing mcp_request utility, accepting app, session ID, request ID, tool name,
and arguments, then update the migrated tools/call sites to use it while
preserving their existing assertions and response handling.

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro Plus

Run ID: c70cb3f3-cf11-4acd-9dca-d4d552c84842

📥 Commits

Reviewing files that changed from the base of the PR and between 9c880e7 and 2fc5c80.

📒 Files selected for processing (1)

• apps/desktop/src-tauri/tests/api_test.rs