Add tests for extractGitHubRepo, isAllDigits and splitCyclesByTestStatus

[magic-peach]

These pure helpers had zero direct test coverage. Covers repo extraction from normal and short module paths, version-suffix repo names, the all-digits check, and cycle classification against a test-only node set including the empty-set case.

Tested with go test ./..., go vet ./... and go build ./..., all pass.

[kubernetes-prow]

[APPROVALNOTIFIER] This PR is NOT APPROVED

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

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

Details

Needs approval from an approver in each of these files:

• OWNERS

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

[skitt]

See https://kubernetes.slack.com/archives/C01672LSZL0/p1789992857325439

/close

[kubernetes-prow]

@skitt: Closed this PR.

Details

In response to this:

See https://kubernetes.slack.com/archives/C01672LSZL0/p1789992857325439

/close

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.