test: add unit tests for LinkDevice scoring

[aaka24]

What type of PR is this?

/kind feature

What this PR does / why we need it:

This PR adds unit tests for the metax device link scoring logic in
pkg/device/metax/score.go.

The scoring functions (LinkDevice.score(), LinkDevices.Score(), and
LinkDevices.String()) previously had no dedicated test coverage.
This change adds table-driven tests covering normal cases and edge cases
without modifying any production code.

Changes (test-only, pkg/device/metax/score_test.go):

• Added tests for LinkDevice.score():

  • Same UUID devices
  • Zero linkZone values
  • Matching linkZone values
  • Different linkZone values

• Added tests for LinkDevices.Score():

  • Empty device list
  • Single device
  • Same-zone devices
  • Different-zone devices
  • Pairwise scoring across multiple devices
  • Mixed link zones
  • Zero link zones

• Added tests for LinkDevices.String():

  • Empty device formatting
  • Non-empty device output validation

This improves coverage of metax topology scoring behavior and helps
prevent regressions in scheduler extender link scoring logic.

Which issue(s) this PR fixes:

Fixes #2410

Special notes for your reviewer:

CI failure appears unrelated to this PR. The failing package is pkg/scheduler, while this PR only adds unit tests for pkg/device/metax/score.go. The new metax tests pass locally with go test ./pkg/device/metax/....

Validation performed locally:

• go test ./pkg/device/metax/... -run TestLinkDevice -v — pass
• gofmt -l pkg/device/metax/score_test.go — clean
• go vet ./pkg/device/metax/... — pass

This PR only adds unit tests and does not change production behavior.

The failure logs point to the scheduler package (pkg/scheduler), specifically around the test-pod-nodefail path. No scheduler files or production code are changed in this PR.

Does this PR introduce a user-facing change?:

No.

Summary by CodeRabbit

• Tests
  • Added coverage for device link scoring across UUID and link-zone combinations.
  • Added tests for scoring device collections, including empty collections and zero link zones.
  • Added validation for readable device collection output, including brackets and UUIDs.

[hami-robot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: aaka24
Once this PR has been reviewed and has the lgtm label, please assign wawa0210 for approval. For more information see the Kubernetes Code Review Process.

The full list of commands accepted by this bot can be found here.

Details

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• OWNERS

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[coderabbitai]

📝 Walkthrough

Walkthrough

Added table-driven unit tests for metax device scoring and collection string formatting. The tests cover UUIDs, link zones, pairwise score accumulation, empty collections, and device output.

Changes

Metax scoring tests

Layer / File(s)	Summary
Device and collection scoring tests pkg/device/metax/score_test.go	Added table-driven tests for LinkDevice.score and LinkDevices.Score, including UUID matches, link-zone combinations, empty and single-device collections, and pairwise scoring.
Collection string output tests pkg/device/metax/score_test.go	Added tests for empty output, bracket delimiters, and UUID inclusion in non-empty collections.

Estimated code review effort: 2 (Simple) | ~10 minutes

Suggested reviewers: archlitchi

Poem

A rabbit checks each link with care,
Matching zones in tidy pairs.
Empty lists and UUIDs shine,
Scores hop neatly line by line.
Tests now guard the metax trail.

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Linked Issues check	✅ Passed	The tests cover the linked issue requirements for LinkDevice.score, LinkDevices.Score, and LinkDevices.String.
Out of Scope Changes check	✅ Passed	The pull request changes only the scoped test file and does not modify production behavior.
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly and concisely describes the added unit tests for LinkDevice scoring, which is the main change.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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[coderabbitai]

Actionable comments posted: 1

🤖 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.

Inline comments:
In `@pkg/device/metax/score_test.go`:
- Around line 166-181: Update the test table’s non-empty case to provide the
exact expected device string, then change the assertions in the t.Run block to
compare result with expected for every case. Retain the existing
bracketed-output validation only if needed, while ensuring mismatched device
order or formatting causes the test to fail.

🪄 Autofix

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro Plus

Run ID: 2abd77bb-2953-4241-8c6e-91f343654c83

📥 Commits

Reviewing files that changed from the base of the PR and between 87d9795 and 2e3438d.

📒 Files selected for processing (1)

• pkg/device/metax/score_test.go

[coderabbitai]

Note

GitHub couldn't provide a complete incremental comparison for this pull request, so CodeRabbit is performing a full review instead. This review may take a little longer.

[archlitchi]

please sync with master to pass the CI

[FouoF]

Thanks for the contribution. These tests cover simple LinkDevice summation and the current formatting of String(). The latter is not a public compatibility contract, so pinning its exact text adds maintenance cost without protecting user behavior. There is no linked defect or reproducible regression, and the current unit-test check is still failing after the requested sync. We are closing this PR. Please choose a maintainer-confirmed issue with an observable failure for the next contribution.

[aaka24]

I understand the concerns regarding testing the String() output and the preference for tests that accompany a maintainer-confirmed bug or reproducible regression. I also appreciate the note about keeping the branch synchronized with master so CI can be evaluated on the latest base.

I'll keep this feedback in mind for future contributions and will focus on issues with observable failures that have maintainer confirmation.

Thanks again for the review and guidance.
@archlitchi @FouoF