test: add unit tests for core/utils and improve nil-safety in helpers

[kincoy]

What type of PR is this?

/kind cleanup

---

What this PR does / why we need it:

This PR improves unit test coverage for several utility functions in core/utils, helping ensure correctness and robustness of logic that supports autoscaling decisions.

Specifically:

• Adds unit tests for:
  • FilterOutNodesFromNotAutoscaledGroups
  • GetOldestCreateTimeWithGpu
  • hasHardInterPodAffinity
  • isVirtualNode
• Fixes potential panic in isVirtualNode when passed a nil node
• Brings test coverage in core/utils/utils.go from 47.4% to 84.6%

before:

after:

---

Which issue(s) this PR fixes:

N/A — test coverage improvement

---

Special notes for your reviewer:

• Safe refactor: no production logic changed, only a nil check added in isVirtualNode
• Tests are table-driven and use testify assertions

---

Does this PR introduce a user-facing change?

NONE

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

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

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

Needs approval from an approver in each of these files:

• cluster-autoscaler/OWNERS

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment

[k8s-ci-robot]

Hi @kincoy. Thanks for your PR.

I'm waiting for a kubernetes member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

Once the patch is verified, the new status will be reflected by the ok-to-test label.

I understand the commands that are listed here.

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes-sigs/prow repository.

[kincoy]

@feiskyer @vadasambar Hi, could you please re-run the failed workflows? They appear to be unrelated to this PR. Thanks🙏!

[vadasambar]

@kincoy sorry I don't have permissions to restart the failed workflow. Can you try creating an empty commit like this to trigger the build (another option is to create a small harmless change like adding new line and removing it later):

git commit --allow-empty -m "Trigger Build"

[kincoy]

@kincoy sorry I don't have permissions to restart the failed workflow. Can you try creating an empty commit like this to trigger the build (another option is to create a small harmless change like adding new line and removing it later):

git commit --allow-empty -m "Trigger Build"

Thanks for your feedback. I found a minor issue in my changes, which has now been fixed. I’ve pushed the update and all tests have passed. Please help review the latest commit to see if it looks good. Thanks again!🙏。

[jackfrancis]

/ok-to-test

[jackfrancis]

return node != nil && node.ObjectMeta.Labels["type"] == VirtualKubeletNodeLabelValue is more concise

[kincoy]

Thanks for the suggestion! I agree the one-liner is more concise, but I opted for the explicit if node == nil form to improve readability and maintainability.

It's quite common to use explicit nil checks, especially when dealing with nested struct access, as it allows easier debugging and extension in the future (e.g., adding logs or metrics inside the nil branch).

Happy to change if we prefer the concise form globally.

[kincoy]

Friendly ping @jackfrancis — this PR has been idle for a while. Would appreciate a review when convenient 🙏