test(e2e): add HttpAgent keepAlive test (#472)

[chimurai]

Add test for #472

Summary by CodeRabbit

• Tests
  • Added end-to-end test for header mutation safety under concurrent keep-alive socket conditions.

[pkg-pr-new]

npm i https://pkg.pr.new/http-proxy-middleware@1267

commit: 66948bc

[coderabbitai]

Caution

Review failed

Pull request was closed or merged during review

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: 8e5abb99-9af1-4d15-86b4-45dbb12821cd

📥 Commits

Reviewing files that changed from the base of the PR and between 5b37301 and 66948bc.

📒 Files selected for processing (1)

• test/e2e/http-proxy-middleware.spec.ts

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📝 Walkthrough

Walkthrough

A new E2E test is added to verify header mutation safety under keep-alive socket contention (issue #472). It imports HttpAgent from node:http, creates a proxy with a shared keep-alive agent limited to a small socket pool, mutates a request header via on.proxyReq, and asserts that 20 concurrent requests all succeed with the correct header and no proxy errors.

Changes

Keep-alive header mutation E2E test

Layer / File(s)

Summary

Keep-alive concurrency header mutation test test/e2e/http-proxy-middleware.spec.ts

Adds HttpAgent import and a new E2E test that creates a proxied app with a shared keep-alive HttpAgent (constrained sockets), registers on.proxyReq to set a custom header, registers on.error to capture errors and emit HTTP 500, fires 20 concurrent GET requests, and asserts all responses succeed, no proxy errors occurred, and every upstream request received the mutated header. The agent is destroyed in a finally block.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~10 minutes

Poem

🐇 Hoppity-hop through the socket queue,
Twenty requests, all waiting in line,
The keep-alive agent shares its glue,
Headers mutate — and turn out just fine!
No proxy errors, the tunnel stays true,
Issue #472, farewell and goodbye! ✨

🚥 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 accurately summarizes the main change: adding an end-to-end test for HttpAgent keepAlive functionality, directly addressing issue #472.
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.

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✨ 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 test-keepalive-agent

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[coveralls]

coverage: 95.183%. remained the same — test-keepalive-agent into master