docs: Add note about Jest warning after frontend tests #1137

[pranitaurlam]

Description

Added documentation explaining that the "Jest did not exit one second after the test run" warning is harmless when all tests pass.

This helps new contributors understand the warning is expected behavior and not an indication of a problem.

Changes Made

• Added a note in the Testing > Frontend section of CONTRIBUTING.md

Files Affected

• CONTRIBUTING.md

Fixes #1137

Summary by CodeRabbit

• Documentation
  • Clarified contributor guidelines (Frontend Testing): notes that the “Jest did not exit…” warning can be expected when tests pass and added troubleshooting guidance to detect open handles and ensure proper test teardown.

[coderabbitai]

📝 Walkthrough

Walkthrough

Added a note to CONTRIBUTING.md (Frontend Testing) stating that the Jest warning "Jest did not exit one second after the test run has completed." can be expected when tests pass; includes guidance to run npx jest --detectOpenHandles and ensure proper teardown to find open handles.

Changes

Cohort / File(s)	Summary
Frontend Testing Documentation CONTRIBUTING.md	Inserted clarification in Frontend Testing section that the Jest exit warning can be harmless when tests pass; added guidance to run npx jest --detectOpenHandles and verify proper teardown to locate root causes.

Estimated code review effort

🎯 1 (Trivial) | ⏱️ ~2 minutes

Poem

🐰 I hopped through docs to make things bright,
A tiny note to calm the fright,
When Jest leaves traces after the run,
Run the detector and you’re nearly done,
Tests are green — the rabbit says: delight!

🚥 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 and concisely summarizes the main change: adding documentation about a Jest warning message.
Linked Issues check	✅ Passed	The PR fully addresses the issue #1137 objectives by documenting that the Jest warning is expected when tests pass and providing guidance on debugging with --detectOpenHandles.
Out of Scope Changes check	✅ Passed	The changes are entirely in scope, modifying only CONTRIBUTING.md to add documentation as required by issue #1137 with no unrelated alterations.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

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✨ Finishing touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment

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[pranitaurlam]

Hi @rahulharpal1603,

I have raised a PR for this issue implementing the documentation for the Jest warning.
Please review and verify. Thanks!

[coderabbitai]

Actionable comments posted: 1

🤖 Fix all issues with AI agents

In `@CONTRIBUTING.md`:
- Around line 68-69: Update the "Jest did not exit one second after the test run
has completed." paragraph in CONTRIBUTING.md to state that Jest reports "open
handles" (which can be unclosed servers, DB connections, sockets, timers, or
file watchers) that keep the Node process alive, that this can indicate resource
leaks and should be investigated rather than ignored, and add guidance to run
"npx jest --detectOpenHandles" and to close resources in test teardown (use
afterEach/afterAll) to fix the root cause.

🧹 Nitpick comments (1)

CONTRIBUTING.md (1)

67-69: Consider linking to additional context.

To provide contributors with more information if they want to investigate further, you could optionally add a reference to issue #1137 or Jest's documentation about async operations.

📚 Optional enhancement with reference link

 > **Note:** After running the frontend tests, you may see a warning:
 > `Jest did not exit one second after the test run has completed.`
-> This is a known behavior and **does not indicate a problem** when all tests pass. It occurs due to async handles that Jest detects but doesn't affect test results or application functionality.
+> This is a known behavior and **does not indicate a problem** when all tests pass. It occurs due to async handles that Jest detects but doesn't affect test results or application functionality. See [issue `#1137`](https://github.com/AOSSIE-Org/PictoPy/issues/1137) for more details.