test(mcp): resolve module-path expectations portably

[czubocha]

Summary

The release workflow's Windows leg fails on six resolveServerModulePath tests in compose.test.js: the tests stub the filesystem with POSIX string literals (/var/task/src/crm.mjs), while the resolver builds candidates with path.resolve — which on Windows yields drive-qualified backslash paths (C:\var\task\src\crm.mjs). No candidate ever matches the stub, so all six tests throw the not-in-package error.

Failing run: https://github.com/serverless/serverless/actions/runs/31014879879/job/92336224583

Test-only change — product code is untouched. The MCP entry executes only on Lambda's Linux runtime; the failures are pure test portability. The stub keys and the expectations are now built with the same path.resolve('/var/task', …) call the resolver uses, so the assertions hold on every runner by construction.

Why this surfaced only post-merge: the cross-platform matrix (Windows/arm) runs only in Release: Framework CLI, which no PR CI exercises — this was the suite's first contact with Windows. The Windows job ran the full 186-suite fleet and this was the only failure.

Impact

release-canary needs: [test-matrix, test-engine], so the failing leg blocked the release cleanly — nothing was published. Merging this unblocks the release train.

Testing

• compose.test.js 57/57 green on POSIX; the win32 resolution shape was probed explicitly to confirm the mismatch mechanism and that the fix keys both sides on the same call.
• The Windows leg itself re-runs on this PR's merge via the release workflow.

Summary by CodeRabbit

• Tests
  • Improved path-resolution test coverage across different operating systems.
  • Updated error-message checks to reflect platform-specific resolved paths.

[Mmarzex]

✅ Snyk checks have passed. No issues have been found so far.

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[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro Plus

Run ID: 6f6d59cb-79fc-4d49-b972-87a9f3f86e6e

📥 Commits

Reviewing files that changed from the base of the PR and between 68210ee and 8261d79.

📒 Files selected for processing (1)

• packages/serverless/test/unit/lib/plugins/aws/mcp/entry/compose.test.js

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📝 Walkthrough

Walkthrough

The MCP compose unit tests now compute expected filesystem paths with path.resolve('/var/task', relative). All relevant stubs, return assertions, and error-message checks use the resolved paths.

Changes

MCP path resolution tests

Layer / File(s)	Summary
Resolve expected filesystem paths packages/serverless/test/unit/lib/plugins/aws/mcp/entry/compose.test.js	Adds an at(relative) helper and uses it for filesystem stubs, successful resolution assertions, and missing-path error assertions.

Estimated code review effort: 1 (Trivial) | ~3 minutes

Possibly related PRs

• serverless/serverless#13681: Both PRs replace hardcoded POSIX test paths with Node.js path resolution utilities.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly describes the test-only change that makes MCP module-path expectations portable across platforms.
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 docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch fix/mcp-compose-tests-windows

Warning

There were issues while running some tools. Please review the errors and either fix the tool's configuration or disable the tool if it's a critical failure.

🔧 ESLint

If the error stems from missing dependencies, add them to the package.json file. For unrecoverable errors (e.g., due to private dependencies), disable the tool in the CodeRabbit configuration.

packages/serverless/test/unit/lib/plugins/aws/mcp/entry/compose.test.js

ESLint skipped: missing config or dependency (missing-dependency). The ESLint configuration references a package that is not available in the sandbox.

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