test(vgpumonitor): add unit tests for metric-sending helpers

[adity1raut]

What type of PR is this?

/kind feature

What this PR does / why we need it:

Adds direct unit tests for sendMetric and sendLegacyMetric in cmd/vGPUmonitor/metrics.go. Both helpers had no direct test coverage — they were only exercised indirectly through the collector-level Describe/Collect test, so the sendMetric error path (mismatched label count) and the nil-descriptor no-op in sendLegacyMetric weren't independently verified.

This is a small, standalone piece of the metrics gap analysis discussed in #2126 (test coverage for the existing vGPUmonitor metrics surface before further changes are layered on top). Companion PR for the scheduler side: #2447.

Which issue(s) this PR fixes:
Relates to #2126

Special notes for your reviewer:

Test-only change, no production code touched. Ran locally:

go test ./cmd/vGPUmonitor/... -short --race -count=1
golangci-lint run ./cmd/vGPUmonitor/...

Does this PR introduce a user-facing change?:

None

AI assistance disclosure: This PR was written primarily by Claude Code (test cases and implementation), based on my own review of the existing metrics.go coverage gaps.

Summary by CodeRabbit

• Tests
  • Added coverage for metric delivery, including successful submissions and legacy metric handling.
  • Added validation for label-count mismatches and missing legacy descriptors.
  • Verified that expected delivery errors are handled without disrupting monitoring behavior.

[hami-robot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: adity1raut
Once this PR has been reviewed and has the lgtm label, please assign shouren for approval. For more information see the Kubernetes Code Review Process.

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No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro Plus

Run ID: 97b235f4-a394-40f3-9bdd-1494340118c5

📥 Commits

Reviewing files that changed from the base of the PR and between 3616313 and 563edc8.

📒 Files selected for processing (1)

• cmd/vGPUmonitor/metrics_test.go

---

📝 Walkthrough

Walkthrough

Added tests for sendMetric and sendLegacyMetric. The tests cover successful delivery, invalid label counts, nil descriptors, and swallowed errors.

Changes

Metric Sender Tests

Layer / File(s)	Summary
Metric delivery and legacy handling tests cmd/vGPUmonitor/metrics_test.go	Added tests for successful metric delivery, invalid label counts, nil legacy descriptors, swallowed errors, and successful legacy delivery.

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

Possibly related PRs

• Project-HAMi/HAMi#2153: Modifies and tests sendMetric and sendLegacyMetric behavior.
• Project-HAMi/HAMi#2326: Adds tests for the same metric helper functions.
• Project-HAMi/HAMi#2240: Adds related metric behavior tests in metrics_test.go.

Suggested reviewers: peachest

Poem

A rabbit checks each metric line,
Valid labels pass the test in time.
Nil descriptors cause no fuss,
Legacy errors stay with us.
“Hop!” says the rabbit, “The suite is green!”

🚥 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 and concisely describes the added unit tests for the metric-sending helpers.
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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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

Flag	Coverage Δ
unittests	64.29% <ø> (+0.20%)	⬆️

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see 3 files with indirect coverage changes

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[FouoF]

Thanks for the contribution. These tests directly exercise two very small metric-emission wrappers, while the same behavior is already exercised through the collector-level tests. This PR does not address a user-visible defect or a maintainer-confirmed gap, and splitting this small coverage exercise from #2447 creates more review and maintenance overhead than project value. We are therefore closing this PR. If a specific metrics regression is found later, please start from a reproducible failure and keep the corresponding fix and regression test together.