Tests: Enhance SSL Proxy.

[oyiz-michael]

What this PR does / why we need it

Converts the placeholder TestSetupSSLProxy into a comprehensive, table-driven test suite that validates SSL passthrough proxy configuration end-to-end.
Maintenance-only scope per project status #13002 — tests only, no production code changes.

Highlights

• 7 scenarios covering:
  • Explicit --enable-ssl-passthrough and implicit port-only configuration
  • Default port behavior (442) and custom port assignment
  • Integration with --default-backend-service
  • Integration with --default-ssl-certificate
  • --enable-ssl-chain-completion interaction
• 15+ assertions against real types (controller.Configuration), including:
  • EnableSSLPassthrough
  • ListenPorts.SSLProxy
  • DefaultService
  • DefaultSSLCertificate
  • global config.EnableSSLChainCompletion
• Clean, table-driven pattern with explicit validators; fixes prior lint issues (unused params, shadowing)

Types of changes

• Tests only (no production code changes)
• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• CVE Report (Scanner found CVE and adding report)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation only

Which issue/s this PR fixes

How Has This Been Tested?

• go test ./pkg/flags -v — all tests pass locally
• Table-driven cases verify:
• Flag/env parsing and precedence
• Defaults when unset (SSL proxy default port 442)
• Positive/negative paths with clear error messages
• Lint clean: resolves previous revive/gocritic warnings (unused/shadowed identifiers)

Checklist:

• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I've read the CONTRIBUTION guide
• I have added unit and/or e2e tests to cover my changes.
• All new and existing tests passed.

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[k8s-ci-robot]

Hi @oyiz-michael. 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.

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[Gacko]

/triage accepted
/kind cleanup
/priority backlog

[Gacko]

/cherry-pick release-1.13

[Gacko]

/cherry-pick release-1.12

[k8s-infra-cherrypick-robot]

@Gacko: once the present PR merges, I will cherry-pick it on top of release-1.13 in a new PR and assign it to you.

In response to this:

/cherry-pick release-1.13

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[Gacko]

/lgtm

[k8s-infra-cherrypick-robot]

@Gacko: once the present PR merges, I will cherry-pick it on top of release-1.12 in a new PR and assign it to you.

In response to this:

/cherry-pick release-1.12

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.

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: Gacko, oyiz-michael

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

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• OWNERS [Gacko]

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[Gacko]

/ok-to-test

[k8s-infra-cherrypick-robot]

@Gacko: new pull request created: #13783

In response to this:

/cherry-pick release-1.13

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.

[k8s-infra-cherrypick-robot]

@Gacko: new pull request created: #13784

In response to this:

/cherry-pick release-1.12

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.

[oyiz-michael]

/assign